Filters
total: 481
Search results for: ACOUSTIC PERFORMANCE
-
Investigation of the vertical distribution of the sound speed of the Gulf of Gdansk in the years 2000-2010
PublicationThe conditions of the acoustic wave propagation in the southern Baltic are much more complex than in other shallow waters. In the typical shallow water, seasonal changes in acoustical conditions in the upper layer, of the depth of about 60-70 m, are observed. They are caused by variation of the annual meteorological conditions. Most often, in the deep water layer, acoustical conditions are stable throughout the year. However, in...
-
Non-invasive investigation of a submerged medieval harbour, a case study from Puck Lagoon
PublicationThis study presents an innovative approach to underwater archaeological prospection using non-invasive methods of seabed exploration. The research focuses on the Puck medieval harbour, a cultural heritage site, and utilises acoustic and optical underwater remote-sensing technology. The primary objectives include optimising the use of Airborne Laser Bathymetry in underwater archaeology, enhancing the filtration process for mapping...
-
A Study of Cross-Linguistic Speech Emotion Recognition Based on 2D Feature Spaces
PublicationIn this research, a study of cross-linguistic speech emotion recognition is performed. For this purpose, emotional data of different languages (English, Lithuanian, German, Spanish, Serbian, and Polish) are collected, resulting in a cross-linguistic speech emotion dataset with the size of more than 10.000 emotional utterances. Despite the bi-modal character of the databases gathered, our focus is on the acoustic representation...
-
Kinedynamics of Spherical Wavefields in Fluid and Dielectric Continua
PublicationDistubances induced by physical sources in fluids or dielectrics maintain their primary character while propagating throughout either of these bi-dynamic continua. The paper defines and illustrates four sets of bi-fields based on four specific fundamental kinedynamic solutions to inhomogeneous wave equations related to quasi-point acoustic and electromagnetic sources.
-
Analiza akustyki Teatru im. Marii Zańkowieckiej we Lwowie na podstawie pomiarów fotogrametrycznych i akustycznych
PublicationUtworzono model komputerowy pola akustycznego w sali widowiskowej Teatru i zbadano zakres możliwych zmian akustyki sali w związku z planowanym remontem sali. Model został skalibrowany na podstawie pomiarów akustycznych w stanie aktualnym. W obliczeniach wykorzystano program komputerowy CATT-Acoustic.
-
The vortex flow caused by sound in a bubbly liquid
PublicationGeneration of vorticity in the field of intense sound in a bubbly liquid in the free half-space is considered. The reasons for generation of vorticity are nonlinearity, diffraction, and dispersion. Acoustic streaming differs from that in a Newtonian fluid. Under some conditions, the vortex flow changes its direction. Conclusions concern streaming induced by a harmonic or an impulse Gaussian beam.
-
A low complexity double-talk detector based on the signal envelope
PublicationA new algorithm for double-talk detection, intended for use in the acoustic echo canceller for voice communication applications, is proposed. The communication system developed by the authors required the use of a double-talk detection algorithm with low complexity and good accuracy. The authors propose an approach to doubletalk detection based on the signal envelopes. For each of three signals: the far-end speech, the microphone...
-
INVESTIGATION OF THE LOMBARD EFFECT BASED ON A MACHINE LEARNING APPROACH
PublicationThe Lombard effect is an involuntary increase in the speaker’s pitch, intensity, and duration in the presence of noise. It makes it possible to communicate in noisy environments more effectively. This study aims to investigate an efficient method for detecting the Lombard effect in uttered speech. The influence of interfering noise, room type, and the gender of the person on the detection process is examined. First, acoustic parameters...
-
Investigation of the laser generated ablation plasma plume dynamics and plasma plume sound wave dynamics
PublicationWe investigated the dynamics of laser generated ablation plasma plume expanding in ambient air and dynamics of the sound wave generated by the expanding plasma. The ablation plasma plume was generated during nanosecond laser micromachining of the thin metal foil. The time-resolved images of the expanding plasma plume and sound wave were captured at several nanosecond intervals. Using captured images the expansion rate of the plasma...
-
Active feedback noise control in the presence of impulsive disturbances
PublicationThe problem of active feedback control of a narrowband acoustic noise in the presence of impulsive disturbances is considered. It is shown that, when integrated with appropriately designed outlier detector, the proposed earlier feedback control algorithm called SONIC is capable of isolating and rejecting noise pulses. According to our tests this guarantees stable and reliable operation of the closed-loop noise cancelling...
-
The nonlinear effects of sound in a liquid with relaxation losses
PublicationThe nonlinear effects of sound in electrolyte with a chemical reaction are examined. The dynamic equations that govern non-wave modes in the field of intense sound are derived, and acoustic forces of vortex, entropy, and relaxation modes are determined in the cases of low-frequency sound and high-frequency sound. The difference in the nonlinear effects of sound in electrolyte and in a gas with excited vibrational degrees of molecules,...
-
Control of mass concentration of reagents by sound in a gas with nonequilibrium chemical reactions
PublicationThe weakly nonlinear dynamics of a chemically reacting gas is studied. Nonlinear interaction of acoustic and nonacoustic types of motion are considered. We decompose the base equations using the relationships of the gas-dynamic perturbations specific for every type of motion. The governing equation for the mass fraction of a reagent influenced by dominating sound is derived and discussed. The conclusions concern the equilibrium...
-
Sounding Mechanism of a Flue Organ Pipe—A Multi-Sensor Measurement Approach
PublicationThis work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed...
-
Application a laboratory stand for multi-symptoms tests for high cyclic fatigue of constructional material
PublicationThis paper describes a need of diagnostics present ship plants according to current technical state. In order to reach competent physical quantity describing fatigue of materials by congregated energy. This paper describes using some diagnostics methods (acoustic emission AE, vibration, thermovision, deformation) in order to definition fatigue state of construction material. The author tries to find correlation between measured...
-
BADANIA ODBIOROWE ŁUKOWEJ KŁADKI DLA PIESZYCH 10T NAD DROGĄ S8 W WARSZAWIE
PublicationThe paper presents in situ load testing of the newly build footbridge over S8 expressway in Warsaw. The most characteristic thing for the structure is a shape of arch girders, which correspond with adjacent half-tunnel acoustic baffles. The paper consists of description of the structure, results of the in-situ static and dynamic load testing, results of the numerical simulations, comparative analysis and final conclusions on the...
-
Split-Beam Echosounder Data from Puck Bay
PublicationThe acoustic data was collected in 2018–2019 in the Bay of Puck in the seasons: autumn, winter, spring. The data was collected during the day and night using three split-beam echosounders with frequencies of 38 kHz, 120 kHz and 333 kHz at a designated study area not far from the city of Hel, while the ship was sailing. To ensure data quality, the echosounders were calibrated and passive noise was measured.
-
Diagnosing wind turbine condition employing a neural network to the analysis of vibroacoustic signals
PublicationIt is important from the economic point of view to detect damage early in the wind turbines before failures occur. For this purpose, a monitoring device was built that analyzes both acoustic signals acquired from the built-in non-contact acoustic intensity probe, as well as from the accelerometers, mounted on the internal devices in the nacelle. The signals collected in this way are used for long-term training of the autoencoder...
-
Velocity Field Characteristics at the Inlet to a Pipe Culvert
PublicationA poorly designed culvert inlet structure causes scouring, which can lead to the collapse of the culvert and significant damage to the neighboring land. A set of laboratory tests was evaluated to examine velocity distribution at the culvert inlet. A three-dimensional acoustic Doppler velocimeterwas used to measure instantaneous flowvelocity upstream of the culvert. The analysis of mean velocities, turbulence strength, and Reynolds...
-
Contactless hearing aid designed for infants
PublicationIt is a well known fact that language development through home intervention for a hearing-impaired infant should start in the early months of a newborn baby's life. The aim of this paper is to present a concept of a contactless digital hearing aid designed especially for infants. In contrast to all typical wearable hearing aid solutions (ITC, ITE, BTE), the proposed device is mounted in the infant's bed with any parts of its set-up...
-
Local dynamics of fluids and dielectrics as the foundation of signal-carrying wave properties
PublicationThis paper develops an original approach to fundamental problems of classical linear acoustics and electromagnetics, proving a crucial role of doubly-dynamic local properties of a propagation medium in supporting wave-like fields able to carry information signals. The proof is composed of two steps concerning, subsequently, fluid acoustics and dielectric electromagnetics. The first step consists in complementing a common, practically...
-
Tracking of the broadband source of the underwater noise in the very shallow water conditions
PublicationThe paper contains the result s, both theoretical and experimental , connected with the tracking of the underwater noise source as small ships, pontoon , diver and so on. The pro blem of security in the shallow water area is the challenge for underwater acousticians. In this paper there is take n into account the detection of the sources that move on the surface of the sea or underwater in shallow...
-
Guitar String Sound Retrieved from Moving Pixels
PublicationThe aim of this study was to develop a method of visual recording and analyzing the vibrations of guitar strings using high-speed cameras and dedicated video processing algorithms. The recording of a plucked string reveals the way in which the deformations propagate, composing the standing and travelling wave. The paper compares the results for a few selected models of classical and acoustic guitars, and it involves processing...
-
Numerical Model of Surface and Quasi-Spherical Sea Noise and Its Application to Analysis of DIFAR Systems
PublicationVarious 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...
-
Multi-source-supplied parallel hybrid propulsion of the inland passenger ship STA.H. Research work on energy efficiency of a hybrid propulsion system operating in the electric motor drive mode
PublicationIn the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology, design has recently been developed of a small inland ship with hybrid propulsion and supply system. The ship will be propelled by a specially designed so called parallel hybrid propulsion system. The work was aimed at carrying out the energy efficiency analysis of a hybrid propulsion system operating in the electric motor drive mode and at...
-
Instantaneous impedance monitoring of AA 7075 aluminum alloy corrosion in borate buffer with admixed chloride ions
PublicationThe study presents a research capabilities of Dynamic Electrochemical Impedance Spectroscopy (DEIS) as a tool used for instantaneous on-line monitoring of corrosion processes on the example of AA 7075 aluminum alloy. A borate buffer with admixed chloride ions in a quantity ranging from 0.05 to 25 mM was used to represent different types of corrosion attack. The surface of samples specimens was evaluated before and after the tests...
-
RADIATION OF HIGH INTENSITY SOUND BY CIRCULAR DISC BY MEANS OF THE NUMERICAL METHOD
PublicationThe main goal of this paper is to find sound pressure distribution radiated by the circular piezoelectric disc that vibrates with the finite amplitude. There has been presented the pressure distribution close to the radiating surface. Also it is shown the sound pressure distribution in the 3D form. The mathematic modeling was carried out on the base of the nonlinear acoustic equation with the proper boundary condition. The axial...
-
Curves of thermodynamic states in some fluids with dispersion
Publicationvariations in the thermodynamic state of a dispersive medium, caused by sound, are studied. A bubbly liquid and a Maxwell fluid are considered as examples. Curves in the plane of thermodynamic states are plotted. They are in fact pictorial images of linear relations of excess pressure and excess density in the acoustic wave which reflect irreversible attenuation of the sound energy. The curves account for the nonlinear generation...
-
A SEARCH OF AN INDUCER GEOMETRY THAT IS BENEFICIAL FOR LIFTING PARAMETERS OF A LIFTED OBJECT OF A SELECTED SHAPE
PublicationThe literature describes acoustic levitation phenomena with the utilization of air squeeze film between the vibrating inducer and the lifted object. The objective of the study is to determine the shape of the inducer with vibration characteristics that would allow the levitation of an object of the assumed geometry. In this paper, the influence of the dimension ratio of the inducer on the frequency of the first mode of vibration...
-
Impact of Spatial Noise Correlation on Bearing Accuracy in DIFAR Systems
PublicationDIFAR 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...
-
Acceleration waves in the nonlinear micromorphic continuum
PublicationWithin the framework of the nonlinear elastic theory of micromorphic continua we derive the conditions for propagation of acceleration waves. An acceleration wave, also called a wave of weak discontinuity of order two, can be treated as a propagating nonmaterial surface across which the second derivatives of the placement vector and micro-distortion tensor may undergo jump discontinuities. Here we obtain the acoustic tensor for...
-
Noise emitted by SKM Trains in Gdansk
PublicationHigh intensity traffic of SKM trains in Gdansk carries a significant level of noise emission. SKM line runs through the central part of the city and therefore in the vicinity of residential areas and recreational facilities. This research was planned and performed to find out what was the real noise emission of SKM trains and to determine whether the measurement noise values are within allowed limits. Individual acoustic events...
-
An adaptive approach to non-destructive evaluation (NDE) of cast irons containing precipitated graphite particles with the help of magnetoacoustic emission
PublicationPhysical properties of cast irons strongly depend on both their microstructure and the presence of casting defects. The paper analyses the possibility of application of magnetoacoustic emission (MAE) for nondestructive detection of flawed cast iron components. The investigated samples containing dross, chunky graphite and lamellar graphite were compared with the reference, flawless, spheroidal cast iron sample. The optimisation...
-
On the Nonlinear Effects of Magnetoacoustic Perturbations in a Perfectly Conducting Viscous and Thermoconducting Gas
PublicationNonlinear effects of planar and quasi-planar magnetosound perturbations are discussed. The plasma is as- sumed to be a Newtonian thermoconducting gas with infinite electrical conductivity permeated by a magnetic field orthogonal to the trajectories of gas particles. Generation of the non-wave modes (magnetoacoustic heating and streaming) in the field of periodic and aperiodic magnetoacoustic perturbations is discussed. The results...
-
Noise effect on parameters of quiet sonar with code modulation
PublicationEarlier publications of the paper authors have shown that the use of code keying mixed with the CW FM sound signal allows the significant reduction in the distance measurement error, compared to classic silent CW FM sonar. In addition to the code modulation parameters, the magnitude of this error is influenced by the received input acoustic noise. The article shows the dependence of the input signal-to-noise ratio and the sound...
-
UNDERWATER NOISE GENERATED BY A SMALL SHIP IN THE SHALLOW SEA
PublicationStudy of the sea noise has been a subject of interest for years. The first work of this scope were published at the turn of the twentieth century by Knudsen (KNUDSEN et al., 1948) and G. Wenz (WENZ, 1962). Disturbances called "shipping noise" are one of the important components of the sea noise. In this work the results of an experimental research of underwater noise produced by a small ship of a classic propulsion are...
-
Acoustics - new services for urban planning, research and education
PublicationThe main purpose of the presented design is twofold, namely: providing detailed information about the noise threats that occur every day in city areas and preventing the noise induced hearing loss especially among young people. An experimental system designed for the continuous monitoring of the acoustic climate of urban areas was developed and implemented within the PLGrid Plus project. The assessment of environmental threats...
-
APPLICATION OF THE HIGH FREQUENCY LINEARIZATION OF THE EAR IN PATIENTS WITH TINNITUS . Metoda linearyzacji narządu słuchu u osób cierpiących z szumami usznymi
PublicationThis paper summarises the problem of tinnitus, hypotheses on its causes and the treatment methods. Moreover, a hypothesis on tinnitus origins is explained, based on the mechanisms of the analog-to-digital conversion and quantization. In addition, this paper describes methods of determining the acoustic intensity and spectra of low- level ultrasonic signals, as well as impedance characteristics of an ultrasound transducer. Furthermore,...
-
Personal adaptive tuning of mobile computer audio
PublicationAn integrated methodology for enhancing audio quality in mobile computers is presented. The key features are adaptation of the characteristics of the acoustic track to the changing conditions and to the user's individual preferences. Original signal processing algorithms are introduced, which concern: linearization of frequency response, dialogue intelligibility enhancement and dynamics processing tuned up to the user's preferences....
-
Unusual streaming in chemically reacting gases
PublicationNonlinear stimulation of the vorticity mode caused by losses in the momentum of sound in the chemically reacting gas, is considered. The instantaneous dynamic equation which describes the nonlinear generation of the vorticity mode, is derived. It includes a quadratic nonlinear acoustic source. Both periodic and aperiodic sound may be considered as the origin of the vorticity flow. In the non-equilibrium regime of the chemical reaction,...
-
Standing Waves in One-Dimensional Resonator Contaning an Ideal Isothermal Gas Affected by the Constant Mass Force
PublicationThe study is devoted to standing acoustic waves in one-dimensional planar resonator which containing an ideal gas. A gas is affected by the constant mass force. Two types of physically justified boundary conditions are considered: zero velocity or zero excess pressure at both boundaries. The variety of nodal and antinodal points is determined. The conclusion is that the nodes of pressure and antinodes of velocity do not longer...
-
Application of dynamic time warping and cepstrograms to text-dependent speaker verification
PublicationThis work provides a description of an automatic speaker verification (ASV) system. In particular, it documents the evolution of all individual stages of the proposed ASV system design from the phase of preprocessing to an operational decision making system. The aim of this research was to achieve the system of the best safety and ease of use in view of users. The objective estimation of this target has been accomplished by assessing...
-
TIRE/ROAD NOISE AND TIRE ROLLING RESISTANCE ON PROTOTYPE PERS SURFACE
PublicationPoroelastic road surfaces are characterized by low noise of tires running on them.Road pavements of this type are promising solution to problems related to traffic noise in cities and on rural roads. Some technical problems still have to be solved, in particular regarding durability and skid resistance on wet surface. Ongoing and planned works are to contribute to create a quiet, durable and safe road surface, which will become...
-
Application of TMS320c67xx signal processors for SONIC-self-optimizing narrowband interference canceler
PublicationThe paper presents a laboratory system for testing active control algorithms of acoustics noise in ducts. An applied algorithm - self-optimizing narrowband interference canceller (SONIC), allows one to remove narrowband disturbances of constant or slowly time-varying frequencies. Example experimental results of using the laboratory system for supression of sinusoidal disturbance are described. An electronic part of the system was...
-
Observing its long-term effects on a short-term, multi-day evaluation of the effectiveness of hearing aid use
PublicationThe main objective of the research study was to develop a method for evaluating the effectiveness of hearing protection with hearing aids tailored to the needs and prevailing conditions in the acoustic environments where the elderly most often reside. The method was also intended to estimate the benefits of hearing aids and allow prediction of such an effect based on a short-term trial. It is noteworthy that a short-term evaluation...
-
Communication Platform for Evaluation of Transmitted Speech Quality
PublicationA voice communication system designed and implemented is described. The purpose of the presented platform was to enable a series of experiments related to the quality assessment of algorithms used in the coding and transmitting of speech. The system is equipped with tools for recording signals at each stage of processing, making it possible to subject them to subjective assessments by listening tests or, objective evaluation employing...
-
Przegląd metod pomiaru temperatury przewodów linii napowietrznych wysokiego napięcia
PublicationW artykule przedstawiono przegląd metod pomiaru temperatury napowietrznych linii wysokiego napięcia stosowanych w celu poprawy niezawodności eksploatacji i w celu wyznaczania dopuszczalnej obciążalności linii. Omówiono system DOL dynamicznej obciążalności linii oraz bezdotykowe metody pomiaru temperatury: pomiar z użyciem pasywnych czujników SAW (ang. Surface acoustic wave sensor), DTS (distributed temperature sensing) z wykorzystaniem...
-
Multibeam Sonar Data Processing for Seafloor Classification
PublicationDespite many years of the development of methodology for sensing the seafloor by means of underwater acoustics, the currently used techniques are still not mature enough and not ready to be utilised in numerous different (i.e. with respect to a water region character, used equipment type etc.) tasks. Therefore the hydroacoustic methods, both utilising vertical observations (e.g. by singlebeam echosounders), as well as those relying...
-
Analiza i ocena smarności olejów w ujęciu energetycznym i działania układu tribologicznego = Analysis and evaluation of oil lubricity from the viewpoint of energy apects and of the tribological system action
PublicationBased on measurement results, an interpretation is presented of the tribological system boundary layer action in the form of a four-ball tester friction node. The evaluation was performed of the boundary layer action understood as transfer of energy Ep resulting from loading the tribological system in a determined time t with work Lp, which may lead to breaking the boundary layer. That energy and time are the values unequivocally...
-
Sound Field Intensity Measurements and Visualization around the Human Head Model . Rozkłąd natężenia pola akustycznego w komorze bezechowej obecności sztucznej głowy i w przypadku braku jej obecności
PublicationThe main goal of this research study was to measure and visualize sound field intensity distribution in and without presence of the human head model. Measurements were performed in the anechoic chamber with the 5 cm grid. Experimental setup consisted of a multitone generator, two loudspeakers, human head model, intensimetric probe, the Cartesian robot applied for precise positioning of the acoustic sensor, and an analyzer. Based...
-
The Doppler effect in a bistatic system for determining the position of moving targets
PublicationThe article presents the theoretical analysis and the results of numerical calculations of the Doppler effect it occurs in a system designed to determine the position and speed of a moving target. The transmitter is the source of the signal and it emits a sinusoidal, acoustic and continuous wave. Signal reflected off a moving target is received by four hydrophones. Based on the signals, four Doppler shifts are determined and inserted...