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Wyznaczanie optymalnej krzywizny toru zwrotnego w rozjazdach dla kolei dużych prędkości na podstawie analizy dynamicznej
PublikacjaW artykule została przedstawiona analityczna metoda wyznaczania krzywizny toru zwrotnego rozjazdu kolejowego posiadającego na swojej długości odcinki zmiennej krzywizny. Taki rozjazd jest dedykowany w głównym stopniu kolejom dużych prędkości. Rozpatrzono dwa odrębne przypadki obejmujące liniowy przebieg krzywizny oraz przebieg nieliniowy, w postaci wielomianowej. Uzyskane rozwiązania problemu pozwalają na przyjmowanie dowolnych...
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Modelling of Geared Multi-Rotor System
PublikacjaIn the paper the method of modelling a speed-varying geared rotor system is presented. The proposed approach enables us to obtain an accurate low-order lumped parameter representation of the investigated system. The final model consists of reduced modal models of an undamped beam/torsional shaft system as well as a spatially lumped model of other linear and nonlinear phenomena including gear mesh interaction.
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Speed sensorless asynchronous motor drive with inverter output lc filter
PublikacjaIn this paper a speed sensorless ac drive with inverter and output LC filter is proposed. A nonlinear, decoupled field oriented control algorithm with a flux and speed close-loop observer is used. In spite of using LC filter on the inverter output, the sensorless system works precisely. That result are obtained as a result of the appropriate estimation and control system use. The theory, simulation, and experimental results are...
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Stability of an Innovative Cold-Formed GEB Section
PublikacjaThis paper is focused on the numerical analysis and experimental test of stability of the cold-formed profile with an innovative GEB cross-section. For the shell model of the axially compressed member, the linear buckling analysis and the nonlinear static analysis were carried out. In the numerical research, the buckling load and the limit load for variable section heights were obtained. Some of the results were compared with 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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AKUSTYCZNY ASPEKT ZASTOSOWANIA BLACHY KORTENOWEJ W EUROPEJSKIM CENTRUM SOLIDARNOŚCI W GDAŃSKU
PublikacjaArtykuł opisuje użycie blachy kortenowej jako dominującego materiału wykończeniowego na elewacjach i we wnętrzach budynku o przesłaniu symbolicznym. Przedstawiono architektoniczne przesłanki, uzasadniające jednorodność zastosowanego materiału. Na tym tle omówiono wpływ blachy kortenowej na akusty-kę pomieszczeń, wraz z podaniem kroków zaradczych redukujących nadmierną pogłosowość i zwiększających stopień rozproszenia dźwięku. Pozytywnym...
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An isogeometric finite element formulation for boundary and shell viscoelasticity based on a multiplicative surface deformation split
PublikacjaThis work presents a numerical formulation to model isotropic viscoelastic material behavior for membranes and thin shells. The surface and the shell theory are formulated within a curvilinear coordinate system,which allows the representation of general surfaces and deformations. The kinematics follow from Kirchhoff–Love theory and the discretization makes use of isogeometric shape functions. A multiplicative split of the surface...
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Comparison of tuning procedures based on evolutionary algorithm for multi-region fuzzy-logic PID controller for non-linear plant
PublikacjaThe paper presents a comparison of tuning procedures for a multi-region fuzzy-logic controller used for nonlinear process control. This controller is composed of local PID controllers and fuzzy-logic mechanism that aggregates local control signals. Three off-line tuning procedures are presented. The first one focuses on separate tuning of local PID controllers gains in the case when the parameters of membership functions of fuzzy-logic...
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Numerical Analysis of Mice Carotid Arteries’ Response Emphasizing the Importance of Material Law Constants’ Validation
PublikacjaIn this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models...
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Introduction to Numerical Simulation
Kursy OnlineCourse description: This interdisciplinary course provides an introduction to computational techniques for the simulation of a broad range of engineering and physical systems. Concepts and methods discussed are widely illustrated by applications drawn from electrical, mechanical, and chemical engineering. Topics include: mathematical formulations of simulation problems; sparse direct and iterative linear system solution techniques,...
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Modal FEM Analysis of Ferrite Resonant Structures
PublikacjaThe finite-element method (FEM) is applied for modal analysis of ferrite-loaded spherical resonators. To improve the efficiency of the numerical calculations, the body-of-revolution (BOR) technique is utilized. Due to the frequency-dependent ferrite permeability, FEM leads to a nonlinear eigenvalue problem that is challenging to solve. To this end, Beyn’s method is proposed. The effectiveness of the proposed approach is confirmed...
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Application of data driven methods in diagnostic of selected process faults of nuclear power plant steam turbine
PublikacjaArticle presents a comparison of process anomaly detection in nuclear power plant steam turbine using combination of data driven methods. Three types of faults are considered: water hammering, fouling and thermocouple fault. As a virtual plant a nonlinear, dynamic, mathe- matical steam turbine model is used. Two approaches for fault detection using one class and two class classiers are tested and compared.
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A Novel Speed Observer for Doubly-Fed Induction Generator
PublikacjaThe purpose of this paper is to show a new state observer for doubly-fed generator. A proposed z-type observer algorithm based on mathematical model of doubly fed generator with additional variables treated as a disturbances has been used. A nonlinear multiscalar control method has been used to control active and reactive power of the generator. All analyses were verified by simulations and experiments tests.
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Adaptive Identification of Underwater Acoustic Channel with a Mix of Static and Time-Varying Parameters
PublikacjaWe consider the problem of identification of communication channels with a mix of static and time-varying parameters. Such scenarios are typical, among others, in underwater acoustics. In this paper, we further develop adaptive algorithms built on the local basis function (LBF) principle resulting in excellent performance when identifying time-varying systems. The main drawback of an LBF algorithm is its high complexity. The subsequently...
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Sterowanie predykcyjne i fuzja danych w systemie dynamicznego pozycjonowania statku
PublikacjaRozprawa doktorska poświęcona jest badaniu zastosowania fuzji danych oraz sterowania predykcyjnego w systemie dynamicznego pozycjonowania statku. W pierwszej części pracy przedstawiono historię rozwoju systemów dynamicznego pozycjonowania, różne metody estymacji położenia statku, metody sterowania oraz cel i tezę pracy. Następnie zaprezentowano model matematyczny statku, kinematykę oraz dynamikę. W kolejnej części przedstawiono...
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Grażyna Grelowska prof. dr hab. inż.
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A note on simple bifurcation of equilibrium forms of an elastic rod on a deformable foundation
PublikacjaWe study bifurcation of equilibrium states of an elastic rod on a two-parameter Winkler foundation. In the article "Bifurcation of equilibrium forms of an elastic rod on a two-parameter Winkler foundation" [Nonlinear Anal., Real World Appl. 39 (2018) 451-463] the existence of simple bifurcation points was proved by the use of the Crandall-Rabinowitz theorem. In this paper we want to present an alternative proof of this fact based...
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A significance of multi slip condition for inclined MHD nano-fluid flow with non linear thermal radiations, Dufuor and Sorrot, and chemically reactive bio-convection effect
PublikacjaThe aim of this research is to discuss the significance of slip conditions for magnetized nanofluid flow with the impact of nonlinear thermal radiations, activation energy, inclined MHD, sorrot and dufour, and gyrotactic micro motile organisms over continuous stretching of a two-dimensional sheet. The governing equations emerge in the form of partial differential equations. Since the resultant governing differential equations...
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Mechanical analysis of eccentric defected bilayer graphene sheets considering the van der Waals force
PublikacjaIn this article, we have tried to simulate nonlinear bending analysis of a double-layered graphene sheet which contains a geometrical imperfection based on an eccentric hole. The first-order shear deformation theory is considered to obtain the governing equations. Also, the nonlinear von Kármán strain field has been assumed in order to obtain large deformations. Whereas the double-layered graphene sheet has been considered, the...
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Accurate simulation-driven modeling and design optimization of compact microwave structures
PublikacjaCost efficient design optimization of microwave structures requires availability of fast yet reliable replacement models so that multiple evaluations of the structure at hand can be executed in reasonable timeframe. Direct utilization of full-wave electromagnetic (EM) simulations is often prohibitive. On the other hand, accurate data-driven modeling normally requires a very large number of training points and it is virtually infeasible...
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About Unusual Diffraction and Thermal Self-Action of Magnetosonic Beam
PublikacjaThe dynamics of slightly diverging two-dimensional beams whose direction forms a constant angle θ with the equilibrium straight magnetic strength is considered. The approximate dispersion relations and corresponding links which specify hydrodynamic perturbations in confined beams are derived. The study is dedicated to the diffraction of a magnetosonic beam and nonlinear thermal self-action of a beam in a thermoconducting gaseous plasma....
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Pursuing Listeners’ Perceptual Response in Audio-Visual Interactions - Headphones vs Loudspeakers: A Case Study
PublikacjaThis study investigates listeners’ perceptual responses in audio-visual interactions concerning binaural spatial audio. Audio stimuli are coupled with or without visual cues to the listeners. The subjective test participants are tasked to indicate the direction of the incoming sound while listening to the audio stimulus via loudspeakers or headphones with the head-related transfer function (HRTF) plugin. First, the methodology...
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Music Mixing Process Controlled by Hand Gestures
PublikacjaW referacie przedstawiono system umożliwiający sterowanie procesami miksowania śladów nagrania muzycznego za pomocą gestów rąk. Przybliżono podstawy wielomodalnej percepcji argumentujące potrzebę powstania tego typu systemu oraz założenia przyjęte w trakcie jego tworzenia. Część sprzętowa systemu składa się z rzutnika multimedialnego, kamery internetowej, komputera klasy PC z zainstalowanym oprogramowaniem systemu oraz ekranu dla...
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Comparison of various speech time-scale modificartion methods
PublikacjaThe objective of this work is to investigate the influence of the different time-scale modification (TSM) methods on the quality of the speech stretched up using the designed non-uniform real-time speech time-scale modification algorithm (NU-RTSM). The algorithm provides a combination of the typical TSM algorithm with the vowels, consonants, stutter, transients and silence detectors. Based on the information about the content and...
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Creating Acoustic Maps Employing Supercomputing Cluster
PublikacjaThe implemented online urban noise pollution monitoring system is presented with regard to its conceptual assumptions and technical realization. A concept of the noise source parameters dynamic assessment is introduced. The idea of noise modeling, based on noise emission characteristics and emission simulations, was developer and practically utilized in the system. Furthermore, the working system architecture and the data acquisition...
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Application of Vector Sensors to Acoustic Surveillance of a Public Interior Space
PublikacjaPrzedstawiono metodę precyzyjnej detekcji i lokalizacji źródeł dźwięku w pomieszczeniach. Wykorzystano wektorowe czujniki akustyczne, dostarczające sygnałów ciśnienia akustycznego i prędkości cząsteczek powietrza. Zaprezentowano metodę lokalizacji źródeł dźwięku na widowni wydarzenia publicznego. Przedstawiono demonstracyjny system zainstalowany w sali wykładowej. System poddano ocenie dokładności na podstawie przeprowadzonych...
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Sacral sound-engineering
PublikacjaOrganologic and campanologic acoustical problems due to applications to sacral objects are characterized on ground of numerous reviewed publications and engineering reports. Participations of several involved research centres, mostly Polish, at solving these problems are evaluated. Some desirable future developments are indicated. Appendices bring examples of documentation on selected investigated objects.
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New approach to railway noise modeling employing Genetic Algorithms
PublikacjaMain goal of this paper was to describe an innovative method of noise prediction based on Genetic Algorithms. First part of the paper addresses the problem of growing noise, mainly in the context of a unified method for measuring noise. Further, Genetic Algorithms are described with regards to their fundamental features. Further a description is provided as to how Genetic Algorithms were used in the area of noise modeling. Next...
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Study of preference for surround microphone techniques, used in the recording of choir and instrumental ensemble
PublikacjaThe aim of this paper is to describe the process of choosing the best surround microphone technique for recording of choir with an instrumental ensemble. First, examples of multichannel microphone techniques including those used in the recording are described. Then, the assumptions and details of music recording in Radio Gdansk Studio are provided as well as the process of mixing of the multichannel recording. The extensive subjective...
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A study on of music features derived from audio recordings examples – a quantitative analysis
PublikacjaThe paper presents a comparative study of music features derived from audio recordings, i.e. the same music pieces but representing different music genres, excerpts performed by different musicians, and songs performed by a musician, whose style evolved over time. Firstly, the origin and the background of the division of music genres were shortly presented. Then, several objective parameters of an audio signal were recalled that...
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Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force
PublikacjaDiagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant...
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Study of probe signal bandwidth influence on estimation of coherence bandwidth for underwater acoustic communication channel
PublikacjaA signal transmitted in a shallow Underwater Acoustic Communication (UAC) channel suffers from time dispersion due to the multipath propagation and the refraction phenomena. This causes intersymbol interference of the received signal and frequency-selective fading observed in its spectrum. Coherence bandwidth is one of the key transmission parameters used for designing the physical layer of a data transmission system to minimise...
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Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublikacjaVarious types of passive sonar systems are used to detect submarines. These activities are complex and demanding. Therefore, computer simulations are most often used at the design stage of these systems. For this reason, it is also necessary to simulate the acoustic ambient noise of the sea. The article proposes a new numerical model of surface and quasi-spherical sea noise and presents its statistical parameters. The results of...
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Acoustic Hysteresis in Flows with Different Kinds of Relaxation and Attenuation
PublikacjaGraphs in the thermodynamic plane acoustic pressure versus excess acoustic density representing acoustic hysteresis, are considered as indicators of relaxation processes, equilibrium parameters of a flow, and kinds of wave exciters. Some flows with deviation from adiabaticity are examined: the Newtonian flow of a thermocon- ducting gas, the flow of a gas with vibrational relaxation, the flow of liquid electrolyte with a chemical...
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Digital waveguide models of the panpipes
PublikacjaW artykule przedstawiono główne cechy syntezy falowodowej. Omówiono cechy instrumentu fletni Pana. Przedyskutowano cechy zaproponowanych dwóch modeli fletni Pana różniących się złożonością obliczeniową. Pokazano szczegóły implementacyjne tych modeli, a także uzyskane wyniki symulacji dźwięków w modelach. Dokonano porównania dźwięków rzeczywistych i uzyskanych w wyniku syntezy falowodowej.
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Heating caused by a non periodic ultrasound. Theory and calculations on pulse and stationary sources.
PublikacjaPrzedstawiono teorię ewolucji ogrzewania na skutek przejścia fali akustycznej każdego typu. Przedyskutowano obliczenia na podstawie nowych wzorów dla fali impulsowej i uderzeniowej. Wzory zgadzają się z klasycznymi w wypadku fal okresowych.
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Confronting representative spectral structures of vocal tract pulse responses
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Language specific spectra generated in the human vocal tract
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Acoustic verification on onomatopoeic sets in contrastive approach
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System of speech signal processing and visualisation for linguistic purposes
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Digital analysis of ethnic speech – extraction of information code
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Standing Waves and Acoustic Heating (or Cooling) in Resonators Filled with Chemically Reacting Gas
PublikacjaStanding waves and acoustic heating in a one-dimensional resonator filled with chemically reacting gas, is the subject of investigation. The chemical reaction of A ! B type, which takes place in a gas, may be reversible or not. Governing equations for the sound and entropy mode which is generated in the field of sound are derived by use of a special mathematical method. Under some conditions, sound waves propagating in opposite...
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"Creating a numerical model of noise conditions based on the analysis of traffic volume changes in cities with low and medium structure.
PublikacjaThe subject of this research study is to analyze noise conditions of the selected area in the city of Gdańsk using data related to traffic volume changes during a day. This is because daily distribution of noise levels is much more helpful for noise control and reduction than traditional maps with Lden levels indicated. Calculations are made with the use of a numerical model developed at the Gdansk Univ. of Technology and implemented...
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Impact of Microphytobenthos Photosynthesis on the Characteristics of the Echo Signal from Baltic Sandy Sediments
PublikacjaThe understanding the influence of biological processes on the characteristics of the signals backscattered by the sea floor is crucial in the development of the hydroacoustical benthic habitat classification techniques. The impact of the microphytobenthos photosynthesis on the acoustical backscattering properties of the Atlantic sandy sediments was previously demonstrated by Holliday et al. (2004) and Wildman and Huettel (2012). To...
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Study of Noise Propagation for Small Vessels
PublikacjaThe paper presents the results of the noise propagation analysis in ship structures tested in a number of AHTS (Anchor Handling Tug Supply) vessels. Statistical Energy Analysis (SEA) based on numerical model developed specially for the purpose of this numerical investigation were conducted. This numerical model enabled the analysis of both the structural elements and the acoustic spaces. For the detailed studies 47 points fixed...
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In Memoriam Professor Jerzy KAPELEWSKI
PublikacjaProfessor Jerzy Kapelewski In Memoriam
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Music Mood Visualization Using Self-Organizing Maps
PublikacjaDue to an increasing amount of music being made available in digital form in the Internet, an automatic organization of music is sought. The paper presents an approach to graphical representation of mood of songs based on Self-Organizing Maps. Parameters describing mood of music are proposed and calculated and then analyzed employing correlation with mood dimensions based on the Multidimensional Scaling. A map is created in which...
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Inhomogeneity of low-noise wearing courses evaluated by tire/road noise measurements using the close-proximity method
PublikacjaPerforming numerous analyses of tire/road noise measurements on low-noise pavements during the last several years, the authors observed significant inhomogeneity of the wearing course in numerous cases, while similar problems were almost non-existent when dense pavements were measured. Three main causes of low-noise pavement inhomogeneity can be defined. The first one is imperfections in the technology used for asphalt mix production...
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Magnetoacoustic Heating of Plasma Caused by Periodic MagnetosoundPerturbations with Discontinuities in a Quasi-Isentropic Magnetic Gas
PublikacjaThe magnetoacoustic heating of plasma by harmonic or periodic saw-tooth perturbations at a trans-ducer is theoretically studied. The planar fast and slow magnetosound waves are considered. The wavevector may form an arbitrary angleθwith the equilibrium straight magnetic field. In view of variableθand plasma-β, the description of magnetosound perturbations and appropriate magnetosound heatingis fairly difficult. The scenario of...
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Impact of Spatial Noise Correlation on Bearing Accuracy in DIFAR Systems
PublikacjaDIFAR type underwater passive systems are one of the more commonly used tools for detecting submarines. At the design stage, which usually uses computer simulations, it is necessary to generate acoustic noise of the sea. It has been shown that correlating noise significantly reduces these errors compared to the assumption that noise is uncorrelated. In addition, bearing errors have been shown to be the same in systems with a commonly...