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Search results for: VARIABLE MASS SYSTEMS
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Analysis of possible application of high-temperature nuclear reactors to contemporary large-output steam power plants on ships
PublicationThis paper is aimed at analysis of possible application of helium to cooling high-temperature nuclear reactor to be used for generating steam in contemporary ship steam-turbine power plants of a large output with taking into account in particular variable operational parameters. In the first part of the paper types of contemporary ship power plants are presented. Features of today applied PWR reactors and proposed HTR reactors...
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Parameter values for topological chaos in the reduced Chialvo model
Open Research DataThe following dataset is connected with a map-based neuron model introduced by D. Chialvo (Chaos, Solitons & Fractals, 5 (3-4) 1995). The reduced version of this model is a one dimensional discrete system which describes the evolution of the membrane voltage when the value of the second variable, the recovery variable, is fixed. We have recently...
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Experimental study of the post tensioned prestressed concrete corbels
PublicationThe results of experimental investigation of 6 symmetrical double prestressed corbels of variable shear span to depth ratio and variable location of prestressing bars are presented in the paper. The post ten- sioned corbels were prestressed with Macalloy 1030 bars of 25 mm in diameter. The results of the tests were compared with the cracking and load carrying capacity of corbels reinforced with passive reinforce- ment. As a result...
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A Model of Thermal Energy Storage According to the Convention of Bond Graphs (BG) and State Equations (SE)
PublicationThe main advantage of the use of the Bond Graphs method and State Equations for modeling energy systems with a complex structure (marine power plants, hybrid vehicles, etc.) is the ability to model the system components of different physical nature using identical theoretical basis. The paper presents a method of modeling thermal energy storage, which is in line with basic BG theory. Critical comments have been put forward concerning...
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Half-Order Modeling of Saturated Synchronous Machine
PublicationNoninteger order systems are used to model diffusion in conductive parts of electrical machines as they lead to more compact and knowledge models but also to improve their precision. In this paper a linear half-order impedance model of a ferromagnetic sheet deduced from the diffusion of magnetic field is briefly introduced. Then, from physical considerations and finite elements simulation, the nonlinear half-order impedance model...
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Scheduling for Industrial Control Traffic Using Massive MIMO and Large Intelligent Surfaces
PublicationIndustry 4.0, with its focus on flexibility and customizability, is pushing in the direction of wireless communication in future smart factories, in particular massive multiple-input multiple-output (MIMO), and its future evolution Large Intelligent Surfaces (LIS), which provide more reliable channel quality than previous technologies. As such, there arises the need to perform efficient scheduling of industrial control traffic...
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Food Classification from Images Using a Neural Network Based Approach with NVIDIA Volta and Pascal GPUs
PublicationIn the paper we investigate the problem of food classification from images, for the Food-101 dataset extended with 31 additional food classes from Polish cuisine. We adopted transfer learning and firstly measured training times for models such as MobileNet, MobileNetV2, ResNet50, ResNet50V2, ResNet101, ResNet101V2, InceptionV3, InceptionResNetV2, Xception, NasNetMobile and DenseNet, for systems with NVIDIA Tesla V100 (Volta) and...
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Variable-Fidelity Simulation Models and Sparse Gradient Updates for Cost-Efficient Optimization of Compact Antenna Input Characteristics
PublicationDesign of antennas for the Internet of Things (IoT) applications requires taking into account several performance figures, both electrical (e.g., impedance matching) and field (gain, radiation pattern), but also physical constraints, primarily concerning size limitation. Fulfillment of stringent specifications necessitates the development of topologically complex structures described by a large number of geometry parameters that...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublicationGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Data from the survey on Gdańsk University of Technology graduates' assessment of studying - the year 2017
Open Research DataThe dataset includes data from the survey on Gdańsk University of Technology graduates’ assessment of studying. The research refers to graduates from the year 2017. The survey was conducted in 2019, two years after the respondents obtained graduate status. The research sample included 1594 respondents. The study referred to as i.a. assessment of whether...
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Distinction of clenbuterol intake from drug or contaminated food of animal origin in a controlled administration trial – the potential of enantiomeric separation for doping control analysis
PublicationThe differentiation of clenbuterol abuse and unintentional ingestion by contaminated meat is crucial with respect to the valuation of an adverse analytical finding in human sports doping control. The proportion of the two enantiomers of clenbuterol may serve as potential discriminating parameter. For the determination of the individual enantiomers, specific methods were developed and validated for the different matrices under investigation...
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Repeated Projectile Impact Tests on Multi-Layered FibrousCementitious Composites
PublicationThis research aims to experimentally evaluate the behaviour of multi-layered fibrous cementitious composites withintermediate Glass Fibre Meshes (GFM) under repeated projectile load. The impact load was subjected through a convexedge projectile needle at a low velocity on cylindrical specimens of three-layered fibrous cementitious composites, whichhave two different steel fibre distributions. In series A mixtures, a constant steel...
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Machine-Learning-Based Global Optimization of Microwave Passives with Variable-Fidelity EM Models and Response Features
PublicationMaximizing microwave passive component performance demands precise parameter tuning, particularly as modern circuits grow increasingly intricate. Yet, achieving this often requires a comprehensive approach due to their complex geometries and miniaturized structures. However, the computational burden of optimizing these components via full-wave electromagnetic (EM) simulations is substantial. EM analysis remains crucial for circuit...
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Variable Data Structures and Customized Deep Learning Surrogates for Computationally Efficient and Reliable Characterization of Buried Objects
PublicationIn this study, in order to characterize the buried object via deep-learning-based surrogate modeling approach, 3-D full-wave electromagnetic simulations of a GPR model has been used. The task is to predict simultaneously and independent of each characteristic parameters of a buried object of several radii at different positions (depth and lateral position) in various dispersive subsurface media. This study has analyzed variable...
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Cost‐efficient performance‐driven modelling of multi‐band antennas by variable‐fidelity electromagnetic simulations and customized space mapping
PublicationElectromagnetic (EM) simulations have become an indispensable tool in the design of contemporary antennas. EM‐driven tasks, for example, parametric optimization, entail considerable computational efforts, which may be reduced by employing surrogate models. Yet, data‐driven modelling of antenna characteristics is largely hindered by the curse of dimensionality. This may be addressed using the recently reported domain‐confinement...
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Iterative Global Sensitivity Analysis Algorithm with Neural Network Surrogate Modeling
PublicationGlobal sensitivity analysis (GSA) is a method to quantify the effect of the input parameters on outputs of physics-based systems. Performing GSA can be challenging due to the combined effect of the high computational cost of each individual physics-based model, a large number of input parameters, and the need to perform repetitive model evaluations. To reduce this cost, neural networks (NNs) are used to replace the expensive physics-based...
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Rapid design optimization of antennas using variable-fidelity EM models and adjoint sensitivities
PublicationPurpose – Development of techniques for expedited design optimization of complex and numerically expensive electromagnetic (EM) simulation models of antenna structures validated both numerically and experimentally. The paper aims to discuss these issues. Design/methodology/approach – The optimization task is performed using a technique that combines gradient search with adjoint sensitivities, trust region framework, as well as...
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Wavelet-based denoising method for real phonocardiography signal recorded by mobile devices in noisy environment
PublicationThe main obstacle in development of intelligent autodiagnosis medical systems based on the analysis of phonocardiography (PCG) signals is noise. The noise can be caused by digestive and respiration sounds, movements or even signals from the surrounding environment and it is characterized by wide frequency and intensity spectrum. This spectrum overlaps the heart tones spectrum, which makes the problem of PCG signal filtrating complex....
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Data from the survey on Gdańsk University of Technology graduates' assessment of studying - the year 2018
Open Research DataThe dataset includes data from the survey on Gdańsk University of Technology graduates’ assessment of studying. The research refers to graduates from the year 2018. The survey was conducted in 2020, two years after the respondents obtained graduate status. The research sample included 727 respondents. The study referred to as i.a. assessment of whether...
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Data from the survey on Gdańsk University of Technology graduates' assessment of studying - the year 2016
Open Research DataThe dataset includes data from the survey on Gdańsk University of Technology graduates’ assessment of studying. The research refers to graduates from the year 2016. The survey was conducted in 2018, two years after the respondents obtained graduate status. The research sample included 1947 respondents. The study referred to as i.a. assessment of whether...
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SEM micrographs and photos of salivary gland stones
Open Research DataThis dataset contains SEM micrographs and high-resolution photographs taken for salivary gland stones (sialolith) extracted during joint studies between Medical University of Gdansk and Gdansk University of Technology.
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Data from the survey on Gdańsk University of Technology graduates' assessment of studying - the year 2015
Open Research DataThe dataset includes data from the survey on Gdańsk University of Technology graduates’ assessment of studying. The research refers to graduates from the year 2015. The survey was conducted in 2017, two years after the respondents obtained graduate status. The research sample included 2553 respondents. The study referred to as i.a. assessment of whether...
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Laser microscope profilometry of (Ce0.80Gd0.20)O1.90 surface before polishing
Open Research DataThe dataset consists of a surface image and topography obtained using a Keyence VK-X1000 confocal laser microscope for (Ce0.80Gd0.20)O1.90 substrate (CGO-20). Imaging was performed to determine surface roughness. The Keyence VK-X1000 uses a 404 nm laser to map and measure the surface of samples via confocal scanning or a wide-field variable focus. The...
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Bounded solutions of odd nonautonomous ODE
PublicationBorsuk-Ulam type argument is used in order to prove exstence of nontrivial bounded solutions to some nonautonomous differential euations which are odd with respect to the spatial variable. A Poincare compactification trick is also applied.
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Selected prtoblems of heat ans mass transfer
e-Learning CoursesThew lecture presentes advanced topics in heat ans mass transfer
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Synteza układu sterowania statkiem morskim dynamicznie pozycjonowanym w warunkach niepewności
PublicationNiniejsza monografia obejmuje zagadnienia związane z syntezą układu dynamicznego pozycjonowania statku w środowisku morskim z zastosowaniem wybranych nieliniowych metod sterowania. W ramach pracy autorka rozważała struktury sterowania z zastosowaniem wektorowej adaptacyjnej metody backstep oraz metod jej pokrewnych, takich jak regulatory MSS (ang. multiple surface sliding), DSC (ang. dynamic surface control), NB (ang. neural backstepping)....
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Data from the survey on Gdańsk University of Technology graduates' qualifications development - the year 2017
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates’ qualifications development. The research refers to graduates from the year 2017. The survey was conducted in 2019, two years after the respondents obtained graduate status. The research sample included 1594 respondents. The study referred to as i.a. to examine...
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Data from the survey on Gdańsk University of Technology graduates' professional careers - the year 2015
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates’ professional careers, from the year 2015. The survey was conducted in 2017, two years after the respondents obtained graduate status. The research sample included 2553 respondents. The study concerned i.a. the percentage of people working among graduates of the...
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Data from the survey on Gdańsk University of Technology graduates' qualifications development - the year 2016
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates’ qualifications development. The research refers to graduates from the year 2016. The survey was conducted in 2018, two years after the respondents obtained graduate status. The research sample included 1947 respondents. The study referred to as i.a. to examine...
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Data from the survey on Gdańsk University of Technology graduates' qualifications development - the year 2015
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates’ qualifications development. The research refers to graduates from the year 2015. The survey was conducted in 2017, two years after the respondents obtained graduate status. The research sample included 2553 respondents. The study referred to as i.a. to examine...
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Data from the survey on Gdańsk University of Technology graduates' professional careers - the year 2016
Open Research DataThe dataset includes data from the survey on the Gdańsk University of Technology graduates’ professional careers, from the year 2016. The survey was conducted in 2018, two years after the respondents obtained graduate status. The research sample included 1947 respondents. The study concerned i.a. the percentage of people working among graduates of the...
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Knowledge-Based Expedited Parameter Tuning of Microwave Passives by Means of Design Requirement Management and Variable-Resolution EM Simulations
PublicationThe importance of numerical optimization techniques has been continually growing in the design of microwave components over the recent years. Although reasonable initial designs can be obtained using circuit theory tools, precise parameter tuning is still necessary to account for effects such as electromagnetic (EM) cross coupling or radiation losses. EM-driven design closure is most often realized using gradient-based procedures,...
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Energy efficiency of electric multiple units in suburban operation
PublicationThis thesis presents approach to analysis of energy efficiency of a suburban rail network, using novel models developed on the Matlab/Simulink basis. Necessary features and requirements for such models were determined thru in-depth review of the source literature in all applicable fields: electrified transportation systems, electric multiple units construction, vehicle drivetrains and finally, existing simulation methods. Existing...
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Computer animation system based on rough sets and fuzzy logic
PublicationA fuzzy logic inference system was created, based on the analysis of animated motion features. The objective of the system is to facilitate the creation of high quality animation by analyzing personalized styles contained in numerous animations. Sequences portraying a virtual character acting with a differentiating personalized style (natural or exaggerated) and various levels of fluidity were prepared and subjectively evaluated....
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Probabilistic sensitivity of limit states of structures. The Monte Carlo simulation
PublicationDesign sensitivity deals with the variation of structural response, implicitly dependent on the design variables of the problem. An attempt is made to implement probabilistic notation in engineering sensitivity analysis. The procedure to implement the sensitivity of a structural limit state to a given basic variable is described in the paper - its main idea, depicted by a flowchart and numerical examples of engineering analysis....
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On analytical solution of stationary two dimensional boundary problem of natural convection
PublicationApproximate analytical solution of two dimensional problem for sta- tionary Navier-Stokes, continuity and Fourier-Kirchho equations describ- ing free convective heat transfer from isothermal surface of half innite vertical plate is presented. The problem formulation is based on the typ- ical for natural convection assumptions: the uid noncompressibility and Boussinesq approximation. We also assume that orthogonal to the plate component...
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An Empirical System Loss Model for Body Area Networks in a Passenger Ferry Environment
PublicationThis paper presents a general empirical system loss model for estimating propagation loss in Body Area Networks in off-body communications at 2.45 GHz in a passenger ferry environment. The model is based on measurements, which were carried out in dynamic scenarios in the discotheque passenger ferry environment. The model consists of three components: mean system loss, attenuation resulting from the variable antenna position on...
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An Empirical System Loss Model for Body Area Networks in a Passenger Ferry Environment
PublicationThis paper presents a general empirical system loss model for estimating propagation loss in Body Area Networks in off-body communications at 2.45 GHz in a passenger ferry environment. The model is based on measurements, which were carried out in dynamic scenarios in the discotheque passenger ferry environment. The model consists of three components: mean system loss, attenuation resulting from the variable antenna position on...
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The Influence of Co-Fermentation of Agri-Food Waste with Primary Sludge on Biogas Production and Composition of the Liquid Fraction of Digestate
PublicationEnergy self-sufficiency is a current trend in wastewater treatment plants. This effect can be achieved by increasing the production of electricity from biogas and by reducing energy consumption for technological processes. One idea, in line with the circular economy concept, is the use of waste rich in organic matter as co-substrates for the fermentation process. The aim of this study was to determine the effect of waste co-fermentation...
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Improved maximum power point tracking algorithms by using numerical analysis techniques for photovoltaic systems
PublicationSolar photovoltaic (PV) panels generate optimal electricity when operating at the maximum power point (MPP). This study introduces a novel MPP tracking algorithm that leverages the numerical prowess of the predictor-corrector method, tailored to accommodate voltage and current fluctuations in PV panels resulting from variable environmental factors like solar irradiation and temperature. This paper delves into the intricate dynamics...
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Troubleshooting of the determination of bisphenol A at ultra-trace levels by liquid chromatography and tandem mass spectrometry
PublicationDetermination of trace amounts of bisphenol A (BPA) may cause problems mainly related to the presence of BPA in solvents (even in LC-MS grade), laboratory vessels, and plastic equipment used for sample preparation. Variable and sometimes significant amounts of BPA present in the background cause problems in obtaining good repeatability of measurements at the ultra-trace levels. Such observations (i.e., poor repeatability of results)...
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The topography of various sialoliths by scanning electron microscopy
Open Research DataThis dataset contains SEM micrographs taken for salivary gland stones (sialolith) extracted during joint studies between the Medical University of Gdansk and Gdansk University of Technology. Three different types of stones were examined, as discussed in the article: 10.1111/odi.13708
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Laser microscope profilometry of (Ce0.80Gd0.20)O1.90 after ∼3 μm surface finish
Open Research DataThe dataset consists of a surface image and topography obtained using a Keyence VK-X1000 confocal laser microscope for (Ce0.80Gd0.20)O1.90 substrate (CGO-20). Imaging was performed to determine surface roughness. The Keyence VK-X1000 uses a 404 nm laser to map and measure the surface of samples via confocal scanning or a wide-field variable focus. The...
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The standard radiated immunity test of an astable multivibrator at a normative field strength
Open Research DataThe dataset presents a result of measurements that are a part of electromagnetic field immunity tests. The radiated, radio frequency, immunity tests were carried out for a typical astable electronic multivibrator. Tests of immunity of electronic systems to radiated radio frequency (RF) disturbances in the frequency range from 80 MHz to 1 GHz are performed...
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The radiated immunity test of an astable multivibrator for various supply voltages
Open Research DataThe dataset presents a result of measurements that are a part of electromagnetic field immunity tests. The radiated, radio frequency, immunity tests were carried out for a typical astable electronic multivibrator supplied from a power supply with an output voltage of 6V and 7.5 V. Tests of immunity of electronic systems to radiated radio frequency (RF)...
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The radiated immunity test of an astable multivibrator in the frequency range from 100 MHz to 300 MHz
Open Research DataThe dataset presents a result of measurements that are a part of electromagnetic field immunity tests. The radiated, radio frequency, immunity tests were carried out for a typical astable electronic multivibrator. Tests of immunity of electronic systems to radiated radio frequency (RF) disturbances in the frequency range from 100 MHz to 300 MHz were...
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On Nature-Inspired Design Optimization of Antenna Structures Using Variable-Resolution EM Models
PublicationNumerical optimization has been ubiquitous in antenna design for over a decade or so. It is indispensable in handling of multiple geometry/material parameters, performance goals, and constraints. It is also challenging as it incurs significant CPU expenses, especially when the underlying computational model involves full-wave electromagnetic (EM) analysis. In most practical cases, the latter is imperative to ensure evaluation reliability....
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Determination of stepped plate thickness distribution using guided waves and compressed sensing approach
PublicationGuided waves recently have attracted significant interest as a very promising research area. The signals registered by a specially designed sensor network are processed to assess the state of the tested structure. Despite the constant development of novel damage detection algorithms employing guided waves, the phenomenon of wave propagation still needs detailed recognizing and understanding for the further progress of non-destructive...
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Quantumness in Diagnostics of Marine Internal Combustion Engines and Other Ship Power Plant Machines
PublicationThe article provides proof that the diagnostics of marine internal combustion engines and other ship power plant machines should take into account the randomness and unpredictability of certain events, such as wear, damage, the variations of mechanical and thermal loads, etc., which take place during machine operation. In the article, the energy E, like the other forms (methods) that it can be converted into (heat and work), is...
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Conception and design of a hybrid exciter for brushless synchronous generator. Application for autonomous electrical power systems = Koncepcja i projekt hybrydowej wzbudnicy bezszczotkowego generatora synchronicznego. Zastosowanie w autonomicznych systemach elektroenergetycznych.
PublicationThis paper covers a subject of a hybrid excitation system for a brushless synchronous generator working with variable speed in an autonomous energy generation system (e.g. airplane power grid). A hybrid excitation system (hybrid exciter) means a synchronous machine with wound-field and permanent magnet excitation. The hybrid exciter supply a dc field current to the synchronous generator field winding through a rotating rectifier....