wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: flicker%20noise
-
DEVELOPMENT OF A COUPLED NUMERICAL AND EXPERIMENTAL APPROACH TO HYDRODYNAMIC NOISE ESTIMATION
PublikacjaThe hydroacoustic signature of ships' propellers can be estimated experimentally through measurements of cavitation-induced pressure fluctuations and the corresponding noise distributions at model scale. These measurements need to be performed in a cavitation tunnel under the propellers operating conditions and are quite sensitive and challenging to perform with sufficient accuracy. In comparison, the numerical approach can be...
-
Traffic Noise Analysis Applied to Automatic Vehicle Counting and Classification
PublikacjaProblems related to determining traffic noise characteristics are discussed in the context of automatic dynamic noise analysis based on noise level measurements and traffic prediction models. The obtained analytical results provide the second goal of the study, namely automatic vehicle counting and classification. Several traffic prediction models are presented and compared to the results of in-situ noise level measurements. Synchronized...
-
Some aspects of noise generated by a small ship in the shallow sea
PublikacjaThe passing and underwater moving objects produce the noises of variable intensity, which significantly increase the overall level of noise in the sea. This applies to both the sonic and ultrasonic range. The excessive levels of underwater noise adversely affects the so-called underwater acoustic climate and is the reason why this phenomenon is intensively investigated from the number of years. The results of experimental work...
-
Distributed System For Noise Threat Evaluation Based On Psychoacoustic Measurements
PublikacjaAn 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....
-
Noise profiling for speech enhancement employing machine learning models
PublikacjaThis paper aims to propose a noise profiling method that can be performed in near real-time based on machine learning (ML). To address challenges related to noise profiling effectively, we start with a critical review of the literature background. Then, we outline the experiment performed consisting of two parts. The first part concerns the noise recognition model built upon several baseline classifiers and noise signal features...
-
Selective monitoring of noise emitted by vehicles involved in road traffic
PublikacjaAn acoustic intensity probe was developed measures the sound intensity in three orthogonal directions, making possible to calculate the azimuth and elevation angles, describing the sound source position. The acoustic sensor is made in the form of a cube with a side of 10 mm, on the inner surfaces of which the digital MEMS microphones are mounted. The algorithm works in two stages. The first stage is based on the analysis of sound...
-
Resistance Noise Higher-Order Spectrums in Nanoparticle Gas Sensors.
PublikacjaPrzedstawiono badania fluktuacji rezystancji sensora gazu wykonanego z nanocząstek WO3. Stwierdzono występowanie składowych o rozkładzie prawdopodobieństwa różnym od rozkładu Gaussa. W celu zwiększenia czułości i selektywności wykrywanych gazów zastosowan do analizy obserwowanych fluktuacji spektra wyższych rzędów.
-
Applications of electrochemical noise technique in stress corrosion cracking diagnosis
PublikacjaW pracy przedstawione zostały rezultaty analizy prądowego szumu elektrochemicznego, generowanego podczas korozji naprężeniowej próbek stali stopowej. W przeciwieństwie do tradycyjnych metod analizy nie zakładano stacjonarności analizowanych sygnałów. Zamiast tego analizie poddana została zmodyfikowana widmowa odpowiedź szumowa o charakterze zależnym od czasu. Rezultaty badań skonfrontowano z wynikami otrzymanymi za pomocą techniki...
-
Analysis and Optimization of Noise in Continuous-Time OTA-C Filters
PublikacjaW pracy przedstawiono ogólną procedurę analizy szumów w filtrach klasy OTA-C czasu ciągłego. Procedura umożliwia analizę filtrów o dowolnej topologii i dowolnego rzędu w ramach rozważanej klasy. W oparciu o opis macierzowy ogólnej struktury filtru OTA-C wyprowadzono ogólne formuły pozwalające na wyznaczanie i optymalizację szumów dowolnego filtru OTA-C. Przedstawione wyniki są użyteczne nie tylko dla klasycznych (dyskretnych lub...
-
Noise Analysis and Optimization of Continuous-Time OTA-C Filters
PublikacjaW pracy przedstawiono efektywną procedurę wyznaczania szumów w filtrach OTA C czasu ciagłego. Procedura wyprowadzona jest w oparciu o ogólny model filtru OTA C oraz jego opis macierzowy. Podano jawne formuły pozwalające okreslić odniesione do wejścia widmo szumów dowolnego filtru rozważanej klasy. Otrzymane wyniki teoretyczne zostały zweryfikowane poprzez porównanie z wynikami otrzymywanymi za pomocą symulatora SPICE dla wybranych...
-
Low noise poroelastic road pavements based on modified asphalt binder
PublikacjaTire/road noise is one of the most important environmental problems related to road traffic. As the most effective way to fight noise is reduction of sound emission from the source, a lot of work is being done to improve tire and road surfaces construction. This paper describes the first “road” results obtained within the SEPOR project, which is focused on developing a low noise poroelastic road surface based on bituminous binder....
-
Reduction of road traffic noise by source measures — present and future strategies
PublikacjaThe current trend worldwide is less focused on reducing road traffic noise. This is in strong contrast to the severe impact of traffic noise to the general health and quality of life. A more holistic and combined strategy is needed. Current international rules and regulations regarding vehicles and tyres are not sufficient to reduce traffic noise levels in an effective way. Calculations show that these regulations will only yield...
-
Tire/Road Noise On Poroelastic Road Surfaces - Results Of Laboratory Measurements
PublikacjaTire/road noise is the most important part of traffic noise for medium and high speed driving both in the case of passenger cars and trucks. The potential to make modification of tires that significantly reduce tire/road noise in nearly over, at least for conventional tires so the only promising action is to improve road pavements. One of the innovative solutions is poroelastic road pavement (PERS) that reduces airflow related...
-
Review and comparison of smoothing algorithms for one-dimensional data noise reduction
PublikacjaThe paper considers the choice of parameters of smoothing algorithms for data denoising. The impact of the window size on smoothing accuracy was analyzed. The parameters of denoising filters were selected with respect to the meansquare error between the computed linear regression and the noisy signal. Finally, we have compared mean, median, SavitzkyGolay, Kalman and Gaussian filter algorithms for the data from the digital sensor....
-
Poroelastic Road Surface – a Promising Road Traffic Noise Abatement Solution
PublikacjaRoad surfaces have a direct impact on the generation of noise by rolling tyres, the main and dominant source of noise of moving vehicles, as well as may affect propagation of noise emitted by all noise sources of a vehicle. Thus there is no doubt that pavement should be considered as one of the major potential road traffic noise abatement measure. Low noise pavements of existing types may in new conditions provide up to 8 dB of...
-
TIRE/ROAD NOISE AND TIRE ROLLING RESISTANCE ON PROTOTYPE PERS SURFACE
PublikacjaPoroelastic 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...
-
Certification of vehicles used for tire/road noise evaluation by CPX method
PublikacjaJednym ze sposobów oceny hałasu opon i nawierzchni drogowych jest metda CPX polegająca na pomiarze hałasu w polu bliskim miejsca współpracy opony z nawierzchnią. Aby uzyskać wysoką dokładność pomiarów niezbędne jest ustanowienie procedur ustanowienie procedur certyfikacyjnych sprzętu pomiarowego a więc głównie pojazdu badawczego. Praca dotyczy procedur certyfikacyjnych wypracowanych przez Grupę Roboczą WG33 ISO/TC43/SC1 oraz w...
-
Methods and means of processing discrete information in networks with a high level of noise
Publikacja -
Reduction of Influence of the High-Frequency Noise on the Results of Surface Topography Measurements
Publikacja -
Investigation of noise threats and their impact on hearing in selected schools - a pilot study.
PublikacjaNoise measurements conducted in selected schools in Gdansk area are presented in this paper. The main aim of this research was to determine noise threats at schools. Some objective measurements of the acoustic climate were performed employing a noise monitoring station engineered at the Multimedia System Department, Gdansk University of Technology. Simultaneously, subjective noise annoyance examinations were carried out among pupils...
-
High quality speech codec employing sines+noise+transients model
PublikacjaA method of high quality wideband speech signal representation employing sines+transients+noise model is presented. The need for a wideband speech coding approach as well as various methods for analysis and synthesis of sines, residual and transient states of speech signal is discussed. The perceptual criterion is applied in the proposed approach during encoding of sines amplitudes in order to reduce bandwidth requirements and...
-
Quality assessments of electrochromic devices: the possibleuse of 1/f current noise
PublikacjaElementy wykorzystujące zjawisko elektrochromizmu, potrafiące zmieniać przezroczystość za pomocą ładowania/rozładowania ładunkiem elektrycznym, wykonano na bazie laminatów pokrytych porowatą strukturą tlenków Ni oraz tlenków Wi-V. Oba laminaty, na które naniesiono przewodzącą warstwę In2O3, przedzielono warstwą elektrolitu. Obserwowano szumy typu 1/f w prądzie I płynącym w trakcie rozładowywania urządzenia. Gęstość widmowa mocy...
-
Tire/road noise measuring principles according to the Close Proximity Method
PublikacjaW pracy podano metody badania hałasu opon samochodowych. Omówiono przyczepy pomiarowe zbudowane w Politechnice Gdańskiej oraz systemy pomiarowe stosowane do pomiaru hałasu opon zgodnie z metodą CPX.
-
Tyre/road noise reduction of poroelastic road surface tested in a laboratory
PublikacjaA so-called poroelastic road surface (PERS) is being developed in Europe. This contains a large percentage of rubber particles mixed with hard aggregate (stone and sand) and bound with polyurethane. This gives high air void content (around 30 %), high elasticity and smooth texture, all of which should give low noise properties. Inthis experiment anominally 30 mm thick sample of PERS was mounted on a steel drum. Various car tyres...
-
The importance of the bottom layer in double-layer porous asphalt for noise reduction
PublikacjaDouble-layer porous asphalt concrete (DPAC) surfaces are generally considered to be the acoustically most effective low noise road surfaces ready for implementation. While DPAC used on highways in warm climates may have an average life of around 8 years, in Scandinavia with severe winter climate DPAC usually survive only about 3 years; partly due to wear of studded tyres. An ongoing project in Sweden, applying DPAC and single-layer...
-
Investigation of RTS Noise in Reverse Polarized Silicon Carbide Schottky Diodes
PublikacjaOne of the method of electronic device quality and reliability evaluation is observation of its inherent noise. The RTS phenomena usually indicates the presence of large defects in the structure of the material of the device, therefore it can be treated as an indicator of technology quality. In the paper authors present results of RTS investigations in reverse polarized Silicon Carbide Schottky diodes. Devices being studied are...
-
Noise Generated by Tyres Designet for Electric Vehicles - Results of Laboratory Experiments
PublikacjaA few years ago, electric and hybrid vehicles were rarely seen on public roads and were considered more as exotic curiosities or even as a sign of extravagance than a practical means of transport. Nowadays the situation has changes significantly. This was caused both by the technical development and legislative actions, as well as the organizational nature promoting the purchace and use of low emission vehicles. Electric vehicles...
-
INFLUENCE OF TEST CONDITIONS ON TYRE/ROAD NOISE MEASURED BY THE DRUM METHOD
PublikacjaTyre/road noise is one of the most important environmental problems related to road traffic. Nowadays a few standard procedures of tyre/road noise measurements are in use. Unfortunately, measurement conditions specified within relevant standards are very different. For example, procedure described in ISO 11819-2 used for pavement investigations requires tyre load of 3200 N and capped inflation pressure of 200 kPa. At the same time...
-
Rolling Resistance And Tire/Road Noise on Rubberized Asphalt Pavement In Poland
PublikacjaThe paper presents results of tire/road noise and rolling resistance measurements performed on stone-matrix asphalt (SMA) that contains rubberized asphalt developed and produced by the company in Poland. Bituminous binder was modified with polymer and additive of crumb rubber. First observations of asphalt mixture with the new kind of modified bitumen used on the field section are presented. Rolling resistance of passenger car...
-
Three solvers for MIMO noise radar clutter cancellation - a performance comparison
PublikacjaThe problem of canceling strong clutter echos in a MIMO noise radar is considered. Execution times of three algorithms is compared. The first solution is a standard Least Squares approach employing Cholesky decomposition of the transmitted signal sample autocorrelation matrix. The second approach is based on careful waveform design which guarantees that the signal sample autocorrelation matrix has Toeplitz structure. This enables...
-
Frequently updated noise threat maps created with use of supercomputing grid
PublikacjaAn innovative supercomputing grid services devoted to noise threat evaluation were presented. The services described in this paper concern two issues, first is related to the noise mapping, while the second one focuses on assessment of the noise dose and its influence on the human hearing system. The discussed services were developed within the PL-Grid Plus Infrastructure which accumulates Polish academic supercomputer centers....
-
Certification requirements for tram noise measurements in terms of today’s expectations in cities
Publikacja -
Barkhausen noise properties measured by different methods for deformed Armco samples
PublikacjaPorównano właściwości sygnału napięciowego efektu Barkhausena (BN) uzyskanego za pomocą 'sondy punktowej' (użytecznej dla badań przemysłowych) oraz cewki otaczającej badany materiał. W pierwszej metodzie mierzono trzy wielkości: V1 - napięcie skuteczne, Nc - liczba impulsów, V2 - napięcie kontrolne z cewki. W drugiej metodzie z napięcia indukowanego w cewce wyznaczano pętlę histerezy B(H), obwiednie z napięcia skutecznego a także...
-
Rolling resistance and tyre/road noise on rubberised asphalt pavement in Poland
PublikacjaThe paper presents results of tyre/road noise and rolling resistance measurements performed on stone mastics asphalt (SMA) that contains rubberised asphalt, developed and produced by a refinery in Poland. Bituminous binder was modified with polymer and addition of crumb rubber. The first observations of asphalt mixture with the new kind of modified bitumen used on the field section are presented. Rolling resistance of passenger...
-
ROSANNE Project: New Procedure for Noise Characterisation of Road Surfaces in Europe
PublikacjaROSANNE is a collaborative project in the 7th EU Framework Programme which aims at harmonising measurement methods for skid resistance, noise emission and rolling resistance of road pavements as a preparation for standardization. The project started in November 2013 and is developing and improving standards in the field of working group CEN/TC 227/WG 5. Regarding the influence of the pavement on the road traffic noise emission,...
-
Signal conditioning for examination of shallow-water acoustic noise correlation properties
PublikacjaThe article describes the process of signal conditioning for examination of acoustic noise correlation properties in shallow water. Knowledge of these properties is very important for the design processes of passive and active hydroacoustic systems. This paper focuses on the above issue from the point of view of passive sonar. In sonar systems, signal processing algorithms operate on both useful acoustic signals, and accompanying...
-
Tracking of the broadband source of the underwater noise in the very shallow water conditions
PublikacjaThe 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...
-
Realistic noise-tolerant randomness amplification using finite number of devices
PublikacjaRandomness is a fundamental concept, with implications from security of modern data systems, to fundamental laws of nature and even the philosophy of science. Randomness is called certified if it describes events that cannot be pre-determined by an external adversary. It is known that weak certified randomness can be amplified to nearly ideal randomness using quantum-mechanical systems. However, so far, it was unclear whether randomness amplification...
-
On the Handling of Outliers in the GNSS Time Series by Means of the Noise and Probability Analysis
PublikacjaThe data pre-analysis plays a significant role in the noise determination. The most important issue is to find an optimum criterion for outliers removal, since their existence can affect any further analysis. The noises in the GNSS time series are characterized by spectral index and amplitudes that can be determined with a few different methods. In this research, the Maximum Likelihood Estimation (MLE) was used. The noise amplitudes...
-
Analysis of the Usefulness of Cheap Audio Recorders for Spectral Measurement of Environmental Noise
PublikacjaEnvironmental noise pollution is nowadays one of the most serious health threats. The impact of noise on the human body depends not only on the sound level but also on its spectral distribution. Reliable measurements of the environmental noise spectrum are often hampered by the very high price of top quality measuring devices. This paper explores the possibility of using much cheaper audio recorders for the frequency analysis....
-
Implementation of constant component filter in measurements of random telegraph signal noise
PublikacjaNoise is generated in all semiconductor devices. The intensity of these fluctuations depends on used elements, manufacturing process, operating conditions and device type. The result noise is a superposition of different kinds of fluctuations like thermal noise, generation-recombination noise, 1/f noise, shot noise and Random Telegraph Signal (RTS) noise. The last one, RTS noise is observed as nonstationary impulse fluctuations....
-
A review of design approaches for the implementation of low-frequency noise measurement systems
PublikacjaElectronic noise has its roots in the fundamental physical interactions between matter and charged particles, carrying information about the phenomena that occur at the microscopic level. Therefore, Low-Frequency Noise Measurements (LFNM) are a well-established technique for the characterization of electron devices and materials and, compared to other techniques, they offer the advantage of being non-destructive and of providing...
-
Investigating Noise Interference on Speech Towards Applying the Lombard Effect Automatically
PublikacjaThe aim of this study is two-fold. First, we perform a series of experiments to examine the interference of different noises on speech processing. For that purpose, we concentrate on the Lombard effect, an involuntary tendency to raise speech level in the presence of background noise. Then, we apply this knowledge to detecting speech with the Lombard effect. This is for preparing a dataset for training a machine learning-based...
-
Evaluation of reinforcement corrosion rate in concrete structures by electrochemical noise measurements
PublikacjaW pracy przedstawiono wyniki obliczeń rezystancji polaryzacyjnej w układzie złożonym z dwóch elektrod (ze stali węglowej oraz elektrody odniesienia), umieszczonych w otulinie betonowej. Szybkość korozji ulega zmianom uzależnionym od stopnia nasiąknięcia betonu roztworem zawierającym jony chlorkowe. Zmiany rezystancji polaryzacyjnej elektrody stalowej oceniane są na podstawie pomiarów prądowego i potencjałowego szumu elektrochemicznego....
-
Low-frequency noise in ZrS3 van der Waals semiconductor nanoribbons
PublikacjaWe report the results of the investigation of low-frequency electronic noise in ZrS3 van der Waals semiconductor nanoribbons. The test structures were of the back-gated field-effect-transistor type with a normally off n-channel and an on-to-off ratio of up to four orders of magnitude. The current–voltage transfer characteristics revealed significant hysteresis owing to the presence of deep levels. The noise in ZrS3 nanoribbons...
-
Creating Dynamic Maps of Noise Threat Using PL-Grid Infrastructure
PublikacjaThe paper presents functionality and operation results of a system for creating dynamic maps of acoustic noise employing the PL-Grid infrastructure extended with a distributed sensor network. The work presented provides a demonstration of the services being prepared within the PLGrid Plus project for measuring, modeling and rendering data related to noise level distribution in city agglomerations. Specific computational environments,...
-
Low frequency noise and DLTS as silicon solar cell characterization tools
PublikacjaPraca zawiera wyniki pomiarów DLTS próbek o powierzchni 1 mm2 krzemowych baterii słonecznych wykazujących znaczne niejednorodności wykryte za pomocą metody LBIV (Light Beam Induced Voltage). Wyniki pomiarów charakterystyk stałoprądowych oraz szumowych tych próbek zostały także przedstawione.
-
Modeling incipient creep damage effects on Barkhausen noise and magnetoacoustic emission.
PublikacjaZaproponowano model fizyczny opisujący zmiany natężenia efektu Barkhausena i emisji magnetoakustycznej podczas procesu degradacji stali ekploatowanych w przemyśle energetycznym.
-
Measurement of noise parameter set in the low frequency range: requirements and instrumentation.
PublikacjaOpisano dwa podstawowe szumowe modele metrologiczne czwórnika: ze źródłami szumów odniesionymi do wejścia i ze zwarciowymi prądami szumów. Parametry szumowe opisujące modele zawierające korelację pomiędzy prądami i/lub napięciami są mierzone przy zastosowaniu metod bezpośrednich i pośrednich. Przedstawiono kilka technik redukcji szumów własnych systemu pomiarowego. Szerzej zaprezentowano dwukanałowy system do pomiaru szumów z komputerowym...
-
Noise reduction in audio employing spectral unpredictability measure and neural net.
Publikacjamodelu psychoakustycznym zostały przedyskutowane. Uczący się algorytm decyzjny, działający w opraciu o sztuczną sieć neuronową wykorzystany został w klasyfikacji składowych na pasożytnicze i użyteczne. Przedstawiona została również nowa iteracyjna procedura obliczania progu maskowania. W pracy zawarte zostały wyniki eksperymentów, oraz konkluzje odnoszące się do przedstawionych algorytmów.