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Search results for: UNDERWATER ACOUSTICS
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Combined spline wavelet decomposition for 3d seafloor imaging from multibeam sonar echoes
PublicationThe paper proposes combined spline-wavelet approach to the raw echoes seaflor imaging from Multibeam Sonar System (MBSS) records. Wavelet representation is closely related to image representation, due to its unique approximations properties. Splines have the best approximation properties among all known wavelets of a given order, so they are best suited for approximating of smooth seafloor surface. Additionaly, wavelet bases have...
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Broadband Sonar with a Cylindrical Antenna
PublicationSkutkiem wzrostu szerokości widma sygnałów w sonarach z płaskimi antenami jest wzrost szerokości odchylanych wiązek, jeżeli beamformer dokonuje kompensacji faz tylko na częstotliwości środkowej widma. W artykule przedstawiono wyniki obliczeń, które odpowiadają na pytanie, czy podobny efekt występuje w szerokopasmowych sonarach z anteną cylindryczną. Obliczenia przeprowadzono dla anten nadawczych o szerokich wiązkach i anten odbiorczych...
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Multimedia System for Environmental Noise Monitoring. [Multimedialny System Monitorowania Hałasu Środowiskowego]
PublicationIntroductionNumerous reports relating to noise threats in Poland indicate that they occur commonly. The noise has an enormous impact on the health and life quality of the human beings. Noise pollution in Poland is greater than in others UE countries, moreover it has been increased recently. Taking into account 2002/49/WE directive related to the control and assessment of environmental noise a necessity of monitoring these threats...
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Microcontroller driven miniaturized digital depth sounder.
PublicationPrzedstawiono schemat blokowy, specyfikację techniczną oraz zasadę działania miniaturowej echosondy cyfrowej, sterowanej mikrokontrolerem PIC16F873.Specjalistyczne oprogramowanie echosondy umożliwia prezentację echogramów w czasie rzeczywistym oraz udostępnianie ich w sieci Internet w typowych przeglądarkach WWW.
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Seabed characterisation using spectral moments of the echo signal
PublicationZbadano użyteczność zastosowania momentów spektralnych obwiedni echa w rozpoznawaniu i klasyfikacji dna morskiego. Przeprowadzono obliczenia momentów spektralnych dla około 15000 ech od dna zarejestrowanych w rejonie Bałtyku Południowego i potwierdzono tezę, że wartości tych momentów skorelowane są silnie z typem dna i rodzajem osadów.
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Application of splines and wavelets along with TIN decimation to 3D imagingof seafloor from multibeam sonar data
PublicationW pracy przedstawiono dwie metody reprezentacji danych batymetrycznych otrzymanych z pomiarów z użyciem sonaru wielowiązkowego. Reprezentacja przy pomocy funkcji sklejanych jest odpowiednia dla baz danych, podczas gdy reprezentacja z wykorzystaniem funkcji falkowych posiada dobre właściwości kompresyjne.
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Indirect Methods of Fish Target Strenght Estimation in Absolute and Logarithmic Domain
PublicationW artykule przedstawiono wyniki estymacji zasobów ryb realizowane w dziedzinie absolutnej (jako estymacja rozproszenia wstecznego) oraz w dziedzinie logarytmicznej (estymacja siły celu).
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Increasing the accuracy of time-varied-gain in digital echosounders
PublicationW artykule przedstawiono problematykę związaną z realizacją precyzyjnej korekcji kompensującej tłumienie dźwięku w wodzie w zastosowaniu do echosond cyfrowych. Pokazano również, że typowo stosowana korekcja prowadzi do kilku decybelowych błędów dla pomiarów realizowanych w wodach płytkich.
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The effect of mechanical coupling on the beam pattern of a multielementarray
PublicationW artykule opisano nową metodę redukcji listków bocznych hydroakustycznej anteny wieloelementowej. Wykorzystano tu efekt ważenia amplitud sygnałów odbieranych przez poszczególne elementy poprzez kontrolowane ich mechaniczne sprzężenie. Opisane zostały wyniki badań kilku modeli anten zbudowanych z pięciu elementów. Wyniki badań zostały zweryfikowane obliczeniami symulacyjnymi. Stwierdzono, zarówno na drodze eksperymentalnej jak...
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Optimising the sounding pulse of the rotational directional transmissionsonar
PublicationPrzedmiotem artykułu jest cyfrowa realizacja techniki ciągłego obrotu wiązki nadawczej w sonarach. W klasycznych rozwiązaniach analogowych polega ona na pobudzaniu elementów anteny hydroakustycznej sygnałami quasi-harmonicznymi o zmieniających się w czasie przesunięcia fazy. W cyfrowej realizacji zmienne w czasie przesunięcia fazy sprowadzają się do pobudzenia elementów anteny sygnałami harmonicznymi o specjalnie dobranych częstotliwościach...
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Instantaneous Heating and Cooling Caused by Periodic or Aperiodic Sound of Any Characteristic Duration in a Gas with Vibrational Relaxation
PublicationThermodynamic relaxation of internal degrees of a molecule's freedom in a gas occurs with some characteristic time. This makes wave processes in a gas behave differently depending on the ratio of characteristic duration of perturbations and the relaxation time. In particular, generation of the secondary non-wave modes by intense sound in a nonlinear flow dependens on frequency. These kinds of interaction are considered in this...
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Evolution of artificial single-cell organisms foraging for resources in a 3-dimensional environment
PublicationForaging for resources is a simple cognitive task that even one-celled biological organisms can ac- complish. We present an Artificial Life system in which artificial unicellular organisms (animats) forage for food in a 3-dimensional simulated liquid environment. The movement of animats is controlled by evolving artificial gene regulatory networks encoded in linear genomes. When an animat consumes enough food, it produces offspring...
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Coastal zone monitoring using Sentinel-1 SAR polarymetry data
PublicationIn recent years the role of the surveillance and security of Polish boundaries has significantly increased. Polish coastal zone monitoring requires various approaches using various technological means in order to ensure the protection of Polish boundaries. In this paper, the authors discuss and present alternatives to underwater surveillance methods of coastal area analysis and monitoring using data retrieved from the newly developed...
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Toward Safe and Efficient Recovery of Gas Munitions Dumped at Sea
PublicationThe proposal of a system for the safe recovery of unexploded ordnance (UXO), chemical weapons (CW) and chemicalwarfare agents (CWA) dumped at sea mainly after WWI and WWII is described in this work. The proposed solutionaddresses the tasks required to neutralise thousands of tons of dumped material and the currently available solutionsand proposed ideas. Requirements concerning the features of a recovery system are defined and...
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Distributed System For Noise Threat Evaluation Based On Psychoacoustic Measurements
PublicationAn innovative system designed for the continuous monitoring of acoustic climate of urban areas was presentedin the paper. The assessment of environmental threats is performed using online data, acquired through a grid ofengineered monitoring stations collecting comprehensive information about the acoustic climate of urban areas.The grid of proposed devices provides valuable data for the purpose of long and short time acoustic climateanalysis....
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Detection of the Incoming Sound Direction Employing MEMS Microphones and the DSP
PublicationA 3D acoustic vector sensor based on MEMS microphones and its application to road traffic monitoring is presented in the paper. The sensor is constructed from three pairs of digital MEMS microphones, mounted on the orthogonal axes. Signals obtained from the microphones are used to compute sound intensity vectors in each direction. With this data, it is possible to compute the horizontal and vertical angle of an incoming sound....
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Cavitation based cleaner technologies for biodiesel production and processing of hydrocarbon streams: A perspective on key fundamentals, missing process data and economic feasibility – A review
PublicationThe present review emphasizes the role of hydrodynamic cavitation (HC) and acoustic cavitation in clean and green technologies for selected fuels (of hydrocarbon origins such as gasoline, naphtha, diesel, heavy oil, and crude oil) processing applications including biodiesel production. Herein, the role of cavitation reactors, their geometrical parameters, physicochemical properties of liquid media, liquid oxidants, catalyst loading,...
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Multimodal Surveillance Based Personal Protection System
PublicationA novel, multimodal approach for automatic detection of abduction of a protected individual, employing dedicated personal protection device and a city monitoring system is proposed and overviewed. The solution is based on combining four modalities (signals coming from: Bluetooth, fixed and PTZ cameras, thermal camera, acoustic sensors). The Bluetooth signal is used continuously to monitor the protected person presence, and in case...
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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...
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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.
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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.
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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.
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Radio Simulcasting at a Glance: a New Look at Broadcasting and Streaming Services
PublicationRadio is by far one of the most popular and accessible medium. With its availability it attracts listeners all around the world. There are numerous ways of delivering content to consumers. The present situation is characterized by the convergence of acoustics, computer science and telecommunications. This paper reviews the current status of radio broadcasting and streaming services. It describes a subjective study concerning different...
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NEW DESIGNS OF CENTRIFUGAL MAGNETIC FLUID SEALS FOR ROTATING SHAFTS IN MARINE TECHNOLOGY
PublicationThe centrifugal magnetic fluid seals have important advantage over the conventional centrifugal seals. They maintain very good sealing capacity at static, medium and high speeds of shaft rotation, with the increased seal lifetime, and minimum torque and static friction. These seals are particularly useful in cases when the angular shaft velocity varies and sometimes decreases to nearly or exactly zero, such as in flywheel applications,...
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System for characterisation and multidimensional imaging of seafloor using multibeam sonar data
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements, underwater object detection and imaging, etc. Also, they are the promising tool in seafloor characterisation and classification, having several advantages over conventional single beam echosounders. The proposed approach to seafloor classification relies on the combined use of three different techniques. In each of them, a set of descriptors...
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An Intergrated Model of Motion, Steering, Positioning and Stabilization of an Unmanned Autonomous Maritime Vehicle
PublicationIn the paper the aim of an interdisciplinary research is presented. The research method is introduced. An object the unmanned autonomous maritime vehicle is briefly described. The key research problem concerns a combined model of the vehicle motion including the loads of lift and hydrodynamic nature. The model takes into account the gravity and displacement forces, resistance and thrust forces, lift and other hydrodynamic forces....
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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...
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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...
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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...
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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...
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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,...
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Adaptive neuro fuzzy and fuzzy decision tree classifiers as applied to sea floor characterization.
PublicationPrzedstawiono wyniki badań wpływu różnych parametrów echa odbitego od dna morskiego na dokładność klasyfikacji typu dna przy pomocy sieci neuronowej z logiką rozmytą i przy pomocy drzew decyzyjnych. W szczególności uwzględniono takie parametry echa jak: energia, amplituda i nachylenie opadającego zbocza, wzbogacone o współczynniki falkowe otrzymane z dyskretnej transformacji falkowej (DWT).
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Fish target strength estimation using multiple echo statistics
PublicationW pracy przedstawiono sposób określania statystycznych właściwości charakterystyki wiązki systemu hydroakustycznego z uwzględnieniem możliwości pojawienia się echo wielokrotnych od jednej ryby. Przedstawiono modele obejmujące dwa teoretyczne przypadki związane z wzajemnym ruchem statku i pojedynczej ryby i pokazano, że posiadają one zbliżone właściwości statystyczne. Rozważania teoretyczne potwierdzone są analizą przykładowych...
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Investigation of influence of space mopdes interaction on nonlinear dynamics of sound beams
PublicationOperatory rzutu na mody są zdefiniowane w dynamice płynów trójwymiarowych. Zostały wyprowadzone równania ewolucyjne. Rezultaty obliczeń numerycznych przedstawione.
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Ring thruster - a preliminary optimisation study of ferrofluid seal and propeller
PublicationThe article reports the course of preliminary examination of a ferrofluid seal applied in liquid environment.A newly built research rig is described, and results of pressure tests performed for different shaft rotationsare discussed. Other studies carried out in the past only referred to the gas environment, while the presentexamination aims at finding an answer to the question whether magnetic liquids can be successfully used...
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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...
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Automatic labeling of traffic sound recordings using autoencoder-derived features
PublicationAn approach to detection of events occurring in road traffic using autoencoders is presented. Extensions of existing algorithms of acoustic road events detection employing Mel Frequency Cepstral Coefficients combined with classifiers based on k nearest neighbors, Support Vector Machines, and random forests are used. In our research, the acoustic signal gathered from the microphone placed near the road is split into frames and converted...
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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...
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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...
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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...
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Influence of Natural Conditions on the Imaging of the Bottom of the Gdańsk Bay by Means of the Side Scan Sonar
PublicationThe interest in underwater resources is the reason for the development of modern hydroacoustic systems, including side sonars, which find numerous applications such as: research of seabed morphology and sediment characteristics, preparation of sea sediment maps, and even in special cases of biocenoses such as sea grass meadows, detection of specific targets at the bottom such as shipwrecks, mines, identification of suitable sites...
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Mathemathical model of radial passive magnetic bearing
PublicationIn the article mathematical radial model of passive magnetic bearings to ocean engineering units has been presented. The units application in underwater thrusters should increase propulsion systems durability and gives lower maintenance costs. The rotor of electric motor is hanging in magnetic field taken from radial passive magnetic bearings. However axial direction maintenance must be controlled with electromagnets and their...
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Web-based 3D processing and dissemination of multibeam sonar data
PublicationThe continuous detailed surveys of the various water bodies over time produce a large and ever-increasing volume and density of underwater sounding data. Three-dimensional data, such as those obtained by multibeam sonar systems, are quite complex to manage, and thus their growing numbers increase the pressure on development of new solutions dedicated to processing them. This paper presents a concept system for web-based dissemination...
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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.
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Robust algorithm for active feedback control of narrowband noise
PublicationThe problem of active control of narrowband acoustic noise is considered. It is shown that the proposed earlier feedback control algorithm called SONIC (self-optimizing narrowband interference canceller), based on minimization of the L2-norm performance measure, can be re-derived using the L1 approach. The resulting robust SONIC algorithm is more robust to heavy-tailed measurement noise, such as the αlpha-stable noise, than the...
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Akustyczna analiza natężenia ruchu drogowego dla systemów zarządzania ruchem
PublicationW pracy przybliżono wybrane zagadnienia z dziedziny zarządzania transportem drogowym w Polsce i na świecie. W tym kontekście pzredstawiono potrzeby rynkowe, wymagania jak i możliwości w zakresie pozyskiwania informacji o aktualnym stanie sieci drogowych. Zaproponowano akustyczną metodę nadzorowania ruchu drogowego i jej możliwości w kontekście systemów zarządzania ruchem. Przedstawiono schemat akwizycji sygnału wraz z danymi odniesienia....
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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...
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EXAMINING INFLUENCE OF VIDEO FRAMERATE AND AUDIO/VIDEO SYNCHRONIZATION ON AUDIO-VISUAL SPEECH RECOGNITION ACCURACY
PublicationThe problem of video framerate and audio/video synchronization in audio-visual speech recognition is considered. The visual features are added to the acoustic parameters in order to improve the accuracy of speech recognition in noisy conditions. The Mel-Frequency Cepstral Coefficients are used on the acoustic side whereas Active Appearance Model features are extracted from the image. The feature fusion approach is employed. The...
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EXAMINING INFLUENCE OF VIDEO FRAMERATE AND AUDIO/VIDEO SYNCHRONIZATION ON AUDIO-VISUAL SPEECH RECOGNITION ACCURACY
PublicationThe problem of video framerate and audio/video synchronization in audio-visual speech recogni-tion is considered. The visual features are added to the acoustic parameters in order to improve the accuracy of speech recognition in noisy conditions. The Mel-Frequency Cepstral Coefficients are used on the acoustic side whereas Active Appearance Model features are extracted from the image. The feature fusion approach is employed. The...
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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...