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Wyniki wyszukiwania dla: NATURAL FREQUENCY MODAL ANALYSIS DYNAMIC LOAD
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REVIEW OF WEATHER FORECAST SERVICES FOR SHIP ROUTING PURPOSES
PublikacjaWeather data is nowadays used in a variety of navigational and ocean engineering research problems: from the obvious ones like voyage planning and routing of sea-going vessels, through the analysis of stability-related phenomena, to detailed modelling of ships’ manoeuvrability for collision avoidance purposes. Apart from that, weather forecasts are essential for passenger cruises and fishing vessels that want to avoid the risk...
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Diagnostic Analysis of Exhaust Gas with A Quick-Changing Temperature from a Marine Diesel Engine Part II / Two Factor Analysis
PublikacjaThe article presents a continuation of research carried out to determine the effect of input parameters (changes in engine structure parameters) on selected output parameters (diagnostic measures), based on quickly changing exhaust gas temperature. A method of determining the simultaneous influence of two input factors (the structure parameter and the engine load) on one output factor was presented, as well as an evaluation...
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Spurious Modes in Model Order Reduction in Variational Problems in Electromagnetics
PublikacjaIn this work, we address an everlasting issue in 2 model order reduction (MOR) in electromagnetics that has 3 remained unnoticed until now. Contrary to what has been 4 previously done, we identify for the very first time spurious 5 modes in MOR for time-harmonic Maxwell’s equations and 6 propose a methodology to remove their negative influence on the 7 reduced order model (ROM) response. These spurious modes 8 have nonzero resonance...
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Curing characteristics, mechanical properties and morphology of butyl rubber filled with ground tire rubber (GTR)
PublikacjaThe results on testing application of ground tire rubber (GTR), as potential filler for butyl rubber, are pre- sented. The GTR content variation, within the range of 10–90 phr, was studied with respect to the vulcanization process, static mechanical properties (tensile strength, elongation-at-break, hardness and resilience), dynamic mechanical properties and the morphology of the obtained vulcanizates. Butyl rubber was characterized...
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Influence of Installation Effects on Pile Bearing Capacity in Cohesive Soils – Large Deformation Analysis Via Finite Element Method
PublikacjaIn this paper, the whole process of pile construction and performance during loading is modelled via large deformation finite element methods such as Coupled Eulerian Lagrangian (CEL) and Updated Lagrangian (UL). Numerical study consists of installation process, consolidation phase and following pile static load test (SLT). The Poznań site is chosen as the reference location for the numerical analysis, where series of pile SLTs...
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Analysis of magnetic field inside thin-layer ferromagnetic objects
PublikacjaResults of the numerical analysis of the magnetic field inside an infinitely long, thin-layer ferromagnetic pipe with and without a barrier were presented in this paper. Two wires with current symmetrically placed on two sides of the pipe are the sources of magnetic field. Numerical calculations for the quasi-steady state for chosen frequency band were carried out in the Flux 2D.
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The short-term flicker severity level measured in the industrial power system supplying the rolling mill motors
Dane BadawczeThe dataset presents a short-term flicker severity level measured on the bus bars of the main switchgear of the industrial power network for the supply of rolling mills. The data were obtained during an experiment whose purpose was to determine a level of short-term and long-term flicker caused by voltage fluctuations. In the virtual application of...
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Experimental tests of reinforced concrete deep-beams
PublikacjaThe paper presents results of experimental research of the reinforced concrete deep beam with a spatial arrangement. Tested structural elements consist of the cantilever deep beam loaded on the height and transverse deep beam with hanging on it another one. The analysis includes crack morphology, effort of steel and load distribution. The article verified effectiveness of two different kind of reinforcement in both tested deep...
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Analiza drgań przewodu jezdnego sieci trakcyjnej w aspekcie oceny jej stanu technicznego.
PublikacjaGórna sieć trakcyjna jest nadal najefektywniejszym sposobem zasilania kolejowych pojazdów elektrycznych. Sieć jezdna nie ma możliwości technicznych redundancji, co wymaga okresowej oceny stanu technicznego w celu zapewnienia prawidłowej współpracy z odbierakami prądu pojazdów. W artykule przedstawiono aspekty oceny stanu technicznego górnej sieci trakcyjnej na podstawie modelowania matematycznego i wybranych badań laboratoryjnych....
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Fast multi-criterial statistical analysis and design optimization of compact microwave couplers
Publikacja—A rapid statistical analysis and yield estimation of compact microwave couplers involving multiple performance parameters has been presented. The analysis is realized using a fast surrogate model representing appropriate characteristic points of the coupler response. Because of less nonlinear dependence of the characteristic points on the structure geometry (compared to the original response, i.e., S-parameters vs. frequency),...
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Resonance microstrip structure with patch of arbitrary convex geometry with the use of field matching technique
PublikacjaAn analysis of the resonance frequency problem of planar microstrip structure with patch of arbitrary convex geometry is presented. A full-wave analysis is employed utilizing a combination of Galerkin’s moment method and field matching technique. In this approach, a field matching technique is adopted to calculate the patch surface current densities, and next the method of moments is utilized to calculate resonance frequencies...
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Calculation of Resonance in Planar and Cylindrical Microstrip Structures Using a Hybrid Technique
PublikacjaA hybrid technique was employed for the analysis of the resonance frequency of thin planar and cylindrical microstrip structures with the patches of arbitrary geometry. The proposed technique utilizes a combination of Galerkin’s moment method and a finite-element method (FEM). In this approach, an FEM is adopted to calculate the patch surface current densities, and a method of moments is utilized to calculate the resonance frequencies...
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Comparison of classical Winter's bracing requirements of compressedtruss chord with stability analysis of 3D truss-model
PublikacjaMost code requirements concerning bracing are based on principles developed by Winter. The present research is devoted tostudy a lateral buckling of truss with linear elastic side supports. The classical Winter's model of truss chord in the case ofout of the truss plane buckling is compared with nonlinear analysis of 3D truss model. Full bracing condition, that permitsthe truss chord to support load level corresponding to an unbraced...
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Identification of residual force in static load tests on instrumented screw displacement piles
PublikacjaOccurrence of the so-called residual force of an unknown value significantly disturbs interpretation of static load tests performed on piles equipped with additional measuring instruments. Screw displacement piles are the piling technology in which the residual force phenomenon is very common. Its formation mechanism is closely related to the installation method of this type of piles, which initiates generation of negative pile...
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High Efficiency Dual-Active-Bridge Converter with Triple-Phase-Shift Control for Battery Charger of Electric Vehicles
PublikacjaAn optimal modulation scheme with triple-phase-shift (TPS) control could increase the efficiency in the entire load range for a dual-active-bridge (DAB) converter under wide output voltage range conditions. Therefore, this study proposes a convergent approach to TPS mode selection, coupled with an optimal modulation scheme, ensuring the circuit’s efficiency over the entire range in the realm of a high-power and high-efficiency...
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ANALYSIS OF THE PROJECT OF INNOVATIVE FLOATING TURBINE
PublikacjaThe design of a floating, innovative device for river water aeration and conversion of mechanical energy to electrical energy required the analysis of a number of geometrical and dynamic features. Such an analysis may be carried out on the basis of existing methods of numerical fluid mechanics. Models of pressures, forces and torques characteristic for the conversion of watercourse energy were developed for two basic concepts of...
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Energy losses reduction in the medium voltage cable line – case study
PublikacjaThe paper presents an analysis of energy losses in a power cable system, which is composed of two 30 kV cable lines. This cable system is located at the seaside holiday area, so the load profile during a year is specific. Energy losses related to reactive power transmission, as well as to currents induced in the sheaths of the cables, are subject to analysis. Measurements were made in the system in order to prepare a computer model...
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Computer Controlled Systems Lab - 2023/2024
Kursy OnlineComputer Controlled Systems Lab The course includes 5 individual projects and their laboratory implementation. The topics:- Job analysis and tuning digital servo- Usage of a PC computer and MatLab package for controlling the dynamic object as a model of the tethered helicopter- Use of C language and the PC to control the plant in real time- Use of assembly language, and a microcontroller to control the plant in real time- Use...
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Computer Controlled Systems Lab - Nowy - Nowy
Kursy OnlineComputer Controlled Systems Lab The course includes 5 individual projects and their laboratory implementation. The topics:- Job analysis and tuning digital servo- Usage of a PC computer and MatLab package for controlling the dynamic object as a model of the tethered helicopter- Use of C language and the PC to control the plant in real time- Use of assembly language, and a microcontroller to control the plant in real time- Use...
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Analysis of Roughness, the Material Removal Rate, and the Acoustic Emission Signal Obtained in Flat Grinding Processes
PublikacjaIn this work, the analysis of the acoustic emission (AE) signal in grinding processes is addressed. The proposed analysis method decomposes the acoustic signal into three frequency ranges. The total energy of each range is determined, as well as the highest frequency. Different grinding experiments were carried out, according to a full factorial design of experiments (DOE), in which feed speed, depth of cut, and transversal step...
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Sensorless Control of Induction Motor Based on Super-Twisting Sliding Mode Observer With Speed Convergence Improvement
PublikacjaThe super twisting sliding-mode observer (ST-SMO) has been proposed to achieve an effective method for alleviating low-order harmonics of measured quantities, issues related to DC drift, and suppression of chattering due to low-frequency sampling. The conventional ST-SMO, on the other hand, suffers from control delay in the convergence trajectory due to the system disturbance, resulting in decreased anti-disturbance capability...
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ARCHITECTURE OF HYDROPOWER PLANTS IN POMORZE
PublikacjaThe history of energetic use of the rivers of Pomerania (Pomorze) is traced from the late Middle Ages. Their potential due to geographical specificity of the region was still attractive in the era of electricity of the19th and the first half of the 20th century. Configuration of the terrain, geological, and natural restrictions, but mainly energetic potential of particular localization were crucial for economical success of the...
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Multi-objective optimization of compact UWB impedance matching transformers using Pareto front exploration and adjoint sensitivities
PublikacjaIn this paper, a technique for fast multi-objective optimization of impedance matching transformers has been presented. In our approach, a set of alternative designs that represent the best possible trade-offs between conflicting objectives (here, the maximum reflection level within a frequency band of interest and the circuit size) is identified by directly exploring the Pareto front. More specifically, the subsequent Pareto-optimal...
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Benchmarking Performance of a Hybrid Intel Xeon/Xeon Phi System for Parallel Computation of Similarity Measures Between Large Vectors
PublikacjaThe paper deals with parallelization of computing similarity measures between large vectors. Such computations are important components within many applications and consequently are of high importance. Rather than focusing on optimization of the algorithm itself, assuming specific measures, the paper assumes a general scheme for finding similarity measures for all pairs of vectors and investigates optimizations for scalability...
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Developing a methodology for model tests of floating platforms in a towing tank of low depth
PublikacjaThe paper presents two ways to mooring model of semi-submersible platform for research in the small depth towing pool. The tested model was made in the likeness of 1:100 Thunder Horse platform moored in the Gulf of Mexico at a depth of 1,920 m. Its mooring system consisted of 16 semi-taut mooring lines (chain-wire-chain) spaced Star-shape and attached at the bottom to the suction piles. The tests were performed in the towing pool...
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Some Aspects of Shear Behavior of Soft Soil–Concrete Interfaces and Its Consequences in Pile Shaft Friction Modeling
PublikacjaThis paper examines the stiffness degradation and interface failure load on soft soil–concrete interface. The friction behavior and its variability is investigated. The direct shear tests under constant normal load were used to establish parameters to hyperbolic interface model which provided a good approximation of the data from instrumented piles. Four instrumented piles were used to obtain reference soil–concrete interface behavior....
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Emergency condition of the ceramic facade of a residential building
PublikacjaThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Emergency condition of the ceramic facade of a residential building
PublikacjaThe paper presents a description of the technical condition of the ceramic cladding of a residential building, the technical condition of which deteriorated significantly after only a few years of operation. The analysis of the influence of the applied design and working solutions on the façade failure frequency was analyzed. The article presents a conceptual solution to bring the building to the proper technical condition in terms...
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Mechanizm współpracy z gruntem pali prefabrykowanych wbijanych w świetle próbnych obciążeń pali oprzyrządowanych
PublikacjaOpis badań i wyniki próbnych obciążeń statycznych dwóch pali prefabrykowanych wbijanych oprzyrządowanych w aparaturę do pomiaru rozkładu siły osiowej wzdłuż trzonu pala. Analiza wpływu czasu i procesu wbijania na charakterystykę osiadania pali prefabrykowanych wbijanych. Identyfikacja siły rezydualnej w palu prefabrykowanym wbijanym i jej wpływ na interpretację pomiarów ekstensometrycznych w próbnym obciążeniu pala. Wnioski na...
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A Formal Approach to Model the Expansion of Natural Events: The Case of Infectious Diseases
PublikacjaA formal approach to modeling the expansion of natural events is presented in this paper. Since the mathematical, statistical or computational methods used are not relevant for development, a modular framework is carried out that guides from the external observation down to the innermost level of the variables that have to appear in the future mathematical-computational formalization. As an example we analyze the expansion of Covid-19....
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Ionospheric scintillations computation using real-time GPS observations
PublikacjaThe following paper presents the results of quasi-real-time determination of the values of phase scintillations indices at the period of ionospheric disturbances that occurred as a consequence of the Sun flares observed on March 7 and 9, 2012. Double-frequency observations with 1-second measurement interval from the EPN (EUREF Permanent Network) network sites located at high latitudes were used for the analysis. To determine the phase...
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Enhancing seismic performance of steel buildings having semi-rigid connection with infill masonry walls considering soil type effects
PublikacjaUnpreventable constructional defects are the main issues in the case of steel Moment-Resisting Frames (MRFs) that mostly occur in the rigidities of beam-to-column connections. The present article aims to investigate the effects of different rigidities of structures and to propose Infill Masonry Walls (IMWs) as retrofitting strategy for the steel damaged buildings. A fault or failure to meet a certain consideration of the soil type...
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Examples of AFM applications in liquid environment
Dane BadawczeImportant advantage of atomic force microscopy (also tunneling microscopy) is the ability to work in different environments (vacuum, controlled atmosphere, liquid environment). The last one, open interesting possibilities, such as imaging of delicate biological materials in their natural state. The use of electrochemical mode allows for the modification...
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The voltage on bus bars of the main switchboard of the car carrier electrical power system at sea trials during a bow thruster start-up
Dane BadawczeThe dataset is a part of the research results on the quality of supply voltage on bus bars of the main switchboard of the ship's electrical power system in different states of ship exploitation. In ships' electrical power systems, disturbances occurring in voltage waveforms on bus bars of the main switchboard are connected mainly with the processes...
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Rhodotorulic Acid and its Derivatives: Synthesis, Properties, and Applications
PublikacjaSiderophores are low molecular weight compounds produced by microorganisms to scavenge iron in iron-deficient environments. Rhodotorulic acid, a natural hydroxamate siderophore, plays a vital role in iron acquisition for fungi and bacteria. As the simplest natural hydroxamate siderophore, it exhibits a high affinity for ferric ions, enabling it to form stable complexes that facilitate iron uptake and transport within microorganisms....
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Measurements of transmission properties of Acoustic Communication Channels
PublikacjaTough transmission properties of shallow water acoustic channels (SWAC) highly limit the use of underwater acoustic communication (UAC) systems. An adaptive matching of modulation and signaling schemes to instantaneous channel conditions is needed for reliabledata communications. This creates, however, unique challenges for designers when compared to radio transmission systems. When communication system elements are in move, the...
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Performance analysis of an rfid-based 3d indoor positioning system combining scene analysis and neural network methods
PublikacjaThe main purpose of this research is to improve localization accuracy of an active Radio Frequency Identification, RFID tag, in 3D indoor space. The paper presents a new RFID based 3D Indoor Positioning System which shows performance improvement. The proposed positioning system combines two methods: the Scene Analysis technique and Artificial Neural Network. The results of both simulation using Log-Distance Path Loss Model and...
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The accuracy of pulse rate estimation from the sequence of face images
PublikacjaThe goal of this paper is to analyze the accuracy of pulse rate estimation from the sequence of face images. Simulated and real signals were used to evaluate two pulse rate estimators; one for frequency domain and the second one for time domain using the autocorrelation function. The results show that the mean difference between the reference measurements and estimated pulse rate values are about 2bpm. In the analysis of short...
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Analysis of radiometric signal in sedimentating suspension flow in open channel
PublikacjaThe article discusses issues related to the estimation of the sedimentating solid particles average flow velocity in an open channel using radiometric methods. Due to the composition of the compound, which formed water and diatomite, received data have a very weak signal to noise ratio. In the process analysis the known determining of the solid phase transportation time delay the classical cross-correlation function is the most...
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Preparation, morphology and properties of natural rubber composites filled with untreated short jute fibres
PublikacjaGreen composites were obtained by incorporation of short jute fibres in natural rubber matrix using a laboratory two-roll mill. The influence of untreated fibre content (1, 2.5, 5, 7.5 and 10 phr) on the mechanical properties, dynamic mechanical properties, swelling properties was examined. The behaviour of prepared green composites under cyclic compression was also investigated. Fibre dispersion in rubber matrix was studied by...
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Factory Acceptance Test – Strain Gauge Measurement, Report no: WOiO /II/123/2014
PublikacjaTested object was 40 meters long jib and its foundation, placed in Gdansk Shiprepair Yard, manufactured by KMK. The contruction was dedicated to the passenger cruise vessel "Quantum of the Seas" The Strain Gauge measurement in different location and load situation was done in order to validate calculation finite element models used during strength analysis for project. The expertise contains: methodology of the measurements, description...
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Factory Acceptance Test – Strain Gauge Measurement - Report no: WOiO /II/88/2014
PublikacjaTested object was 40 meters long jib and its foundation, placed in Gdansk Shiprepair Yard, manufactured by KMK. The contruction was dedicated to the passenger cruise vessel "North Star" The Strain Gauge measurement in different location and load situation was done in order to validate calculation finite element models used during strength analysis for project. The expertise contains: methodology of the measurements, description...
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The use of Response Surface Methodology for reliability estimation of composite engineering structures
PublikacjaStability loss is one of the key issues in the analysis of shells made of composite materials. This paper aims at finding the variation of the critical or limit value of the load resulting from geometric imperfections. An axially compressed 16-layer cylindrical panel model is considered. The imperfections of the panel are simulated as random fields. The parameters of these fields are used as the basic variables of the reliability...
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The mechanism of grouting action under the base of bored pile
PublikacjaThe grouting under the base of bored pile is carried out in order to reduce pile settlement and improve its bearing capacity. The principal aim of grouting is to introduce an initial force between the soil and the pile base. In non-cohesive soil, the grouting can also enlarge the pile base area and therefore improve the base resistance. The example of static load tests on instrumented bored piles installed with and without grouting...
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ANALYSIS OF BEARING CLEARANCE AND WIDTH OF OIL GROOVE ON CHARACTERISTIC OF FLUID FILM IN HYDRODYNAMIC MAIN CRANKSHAFT BEARINGS
PublikacjaAbstract Paper represents analysis of influence of oil groove width and bearing clearance on characteristics of oil film in hydrodynamic journal main crankshaft bearing. Analysis was performed in purpose to define influence of bearing clearance and dimensions of oil groove on static characteristics and manufacturability of half shelf bearings in industrial high-volume production. Computer simulations was made using ARTbear program...
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Channel Impulse Response Measurements at mmWave Band in Office and Conference Rooms
PublikacjaIn this paper, the measurements of the channel impulse response at mmWave band in office and conference rooms are described. The central frequency is 27 GHz with a bandwidth of 400 MHz. The description of the used measurement stand and considered environments are presented. The initial analysis of the power delay profile, mean delay, and RMS delay spread allows preliminary conclusions to be drawn that there is a significant impact...
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Intensification of thermal convection near electric devices using flat screens – computer modelling
PublikacjaIntensification of natural thermal convection near electric devices is possible by application of additional elements as screens creating convection canals close to the device. In the earlier authors paper the results of the analysis of thermal convection with the use of only one additional screen close to the electric device were presented. This paper presents computer modelling of thermal convection when two screens near the...
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MAGNETOACOUSTIC HEATING AND STREAMING IN A PLASMA WITH FINITE ELECTRICAL CONDUCTIVITY
PublikacjaNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. Plasma is assumed to be an ideal gas with a finite electrical conductivity permeated by a magnetic filed orthogonal to the trajectories of gas particles. the excitation of non-wave modes in the filed of intense magnetoacoustic perturbations, i.e., magnetoaciustic heating and streaming, is discussed. The analysis includes a derivation if instantaneous...
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AUTOMATIC OPTIMIZATION OF ADAPTIVE NOTCH FILTER’S FREQUEN CY TRACKING
PublikacjaEstimation of instantaneous frequency of narrowband com- plex sinusoids is often performed using lightweight algo- rithms called adaptive notch filters. However, to reach high performance, these algorithms require careful tuning. The paper proposes a novel self-tuning layer for a recently intr o- ducedadaptive notch filtering algorithm. Analysis shows th at, under Gaussian random-walk type assumptions, the resultin g solution converges...
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Automatic Optimization Of Adaptive Notch Filter’s Frequency Tracking
PublikacjaEstimation of instantaneous frequency of narrowband com- plex sinusoids is often performed using lightweight algo- rithms called adaptive notch filters. However, to reach high performance, these algorithms require careful tuning. The paper proposes a novel self-tuning layer for a recently intr o- ducedadaptive notch filtering algorithm. Analysis shows th at, under Gaussian random-walk type assumptions, the resultin g solution converges...