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Search results for: FLICKER NOISE
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Design of low noise preamplifers for characterization of LSCO bolometers
PublicationW artykule przedstawiono wymagania stawiane układom do pomiaru szumów bolometrów. Ze względu na niski poziom mierzonych szumów układy te wymagają zastosowania niskoszumnych przedwzmacniaczy i układów ustalających punkt pracy badanych detektorów. Omówiono konstrukcje dwóch przedwzmacniaczy z zintegrowanymi układami polaryzacji. Przedstawiono wyniki pomiarów szumów w zakresie częstotliwości 10-90Hz. Przedstawiono możliwości ulepszenia...
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Substrate noise modeling in early floorplanning of MS-SOCs.
PublicationW pracy zaproponowano model częstotliwościowy bloków analogowych wrażliwych na zakłócenia oraz bloków cyfrowych generujących zakłócenia w systemach mieszanych realizowanych na wspólnym podłożu krzemowym. Zaproponowane modele zostały wykorzystane w oprogramowaniu optymalizującym rozmieszczenie bloków funkcjonalnych na struktórze krzemowej. Dzieki użyciu procedur optymalizacyjnych uzyskano znaczącą redukcje poziomu zakłóceń przy...
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IMPULSE NOISE ASSOCIATED WITH FIRING HANDHELD MILITARY WEAPONS
PublicationSports, hunting and military shooting grounds are well known sources of noise that can be disruptive both for people present at those facilities, as well as for people and animals that live nearby. What is more, shooters are also subjected to very painful and dangerous impulse noise. The paper discusses the issues related to the noise immission during firing of small firearms of military type that are typical for Poland. The experiments...
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Speed dependency of temperature effects on road traffic noise
PublicationRecently, a new literature review on the influence of temperature on tire/road noise became available, based on a compilation of large amounts of data from empirical research. This review showed that the effect of temperature is roughly double of that previously assumed and taken account of in international standards. This makes temperature one of the main sources of error in measurement results. Furthermore, it suggested that...
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Tire camber angle influence on tire-pavement noise
PublicationTaking into account tire-pavement noise and tires classification with respect to noise emission special measurement methods are usually used. When two of them are applied (the Laboratory Drum Method (DR) and the Close-Proximity Method (CPX)) the investigator has to be sure that the position of the tire is correct. The authors of this paper thought about tire position as tire (wheel) alignment in particular tire camber angle. They...
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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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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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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...
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Improving Objective Speech Quality Indicators in Noise Conditions
PublicationThis work aims at modifying speech signal samples and test them with objective speech quality indicators after mixing the original signals with noise or with an interfering signal. Modifications that are applied to the signal are related to the Lombard speech characteristics, i.e., pitch shifting, utterance duration changes, vocal tract scaling, manipulation of formants. A set of words and sentences in Polish, recorded in silence,...
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Methods of electrochemical noise analysis for investigation of corrosion processes
PublicationKorozja elektrochemiczna może być oceniana za pomocą przpływu ładunków między korodującym metalem a elektrolitem. Zwykle, przpływ ładunku obserwuje się w układzie trzech elektrod jako fluktuacje prądu i napięcia (szumy elektrochemiczne). Na podstawie analizy szumów elektrochemicznych można wykrywać różne rodzaje korozji. Korozja jednorodna jest oceniana za pomocą wartości rezystancji polaryzacyjnej występującej między metalem a...
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Projects of noise level on railway lines
Open Research DataProjects of acoustic signals from railway lines for further analysis in the BK Connect program.
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projects of noise level on railway lines
Open Research DataProjects of acoustic signals from railway lines for further analysis in the BK Connect software.
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Hydrazone Linker as a Useful Tool for Preparing Chimeric Peptide/Nonpeptide Bifunctional Compounds
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"Walerian Wróbel - Zwei Blicke auf das Unrecht am jungen Zwangsarbeiter"
PublicationZur Ausstellung Die tragische Geschichte über das Schicksal des jungen polnischen Zwangsarbeiters Walerian Wróbel (2. April 1925 in Falków — 25. August 1942 in Hamburg) bewegt heute noch viele Menschen. Er wurde im Alter von nur 17 Jahren nach einem Urteil des Sondergerichts Bremen von den Nationalsozialisten hingerichtet. In dieser Ausstellung geht es jedoch nicht um Walerian Wróbel selbst, sondern um den Versuch der...
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On sequences of the white noises
PublicationPodano dowód mocnego prawa wielkich liczb dla funkcjonałów gaussowskich.
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Advanced operating methods
PublicationSelected operating methods of resistive gas sensors were presented. The methods utilize flicker noise (1/f noise), which gives additional information about ambient gas when compared with the recorded changes of DC resistance only. Methods of flicker noise measurements were outlined. Recently developed prototype gas sensors comprising golden nanoparticle functionalized with organic ligands can generate intense flicker noise induced...
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Low Noise Poroelastic Road Pavements Based On Bituminous Binder
PublicationTire/road noise is the dominant source of traffic noise. It depends both on the tire design and on the characteristics of road pavements as well as on the vehicles’ operating conditions. Due to the fact that conventional (pneumatic) car tires have almost reached the limits of their ability to further reduce their noisiness, it is widely believed that the additional reduction of tire noise will be possible mainly through modifications...
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Irregular variations in GPS time series by probability and noise analysis
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An improved frequency estimator for an adaptive active noise control scheme
PublicationAn improved frequency tracker is proposed for the recently introduced self optimizing narrowband interference canceller (SONIC). The scheme is designed for disturbances with quasi-linear frequency modulation and, under second-order Gaussian random-walk assumption, can be shown to be statistically efficient. One real-world experiment and several simulations show that a considerable improvement in disturbance rejection may be achieved...
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Investigation of the underwater noise produced by ships by means of intensity method
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Identification of inherent noise components of semiconductor devices on an example of optocouplers
PublicationIn the paper, a method of estimation of parameters of Gaussian and non-Gaussian components in the noise signal of semiconductor devices in a frequency domain is proposed. The method is based on composing estimators of two spectra, corresponding to noise (Gaussian component) and two-level RTS noise (non-Gaussian component). The proposed method can be applied for precise evaluation of the corner RTS frequency fRTS in the noise...
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Evaluation of excessive noise effects on hearing employing psychoacoustic dosimetry
PublicationResearch results regarding the noise impact on hearing applying the concept of the Psychoacoustic Noise Dosimetry (PND) are presented. The general characteristics of the PND algorithm are discussed. Additionally, the results of hearing examinations conducted in the laboratory conditions are shown. The main objective of the research was to determine the time needed for the Temporary Threshold Shift to reverse. The results were used...
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Directivity of tire/road noise emission for selected tires and pavements
PublicationPraca pośwoęcona jest kierunkowości emisji hałasu opon i nawierzchni drogowych. Opony są dominującym źródłem haasu w pojaździe poruszającym się w typowych warunkach ruchu drogowego. Hałas ten nie jest bezkierunkowy jak to przyjmuje się w modelach obliczeniowych hałasu. Takie założenia wynikają z ograniczonej dostępności danych dotyczących kierunkowości i mogą prowadzić do niedokładności przy prognozowaniu hałasu drogowego. Praca...
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Pitting corrosion characterization by electrochemical noise measurements on asymmetric electrodes
PublicationKorozja wżerowa stali nierdzewnych może być wykryta za pomocą obserwacji charakterystycznych sygnałów prądowych, jakie płyną między dwiema elektrodami metalowymi. W artykule proponuje się wyznaczanie funkcji bispektrum dla układu dwóch elektrod o istotnie różnej powierzchni narażonej na występowanie korozji. Proponowana metoda została zastosowana do analizy korozji wżerowej stali 0H18N9 powstającej pod wpływem 1M roztworu FeCl3...
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Dedicated power supply subsystem for ultra-low noise preamplifiers
PublicationIn field of electronics there is need for low-noise amplifiers. Noise have the most important influence on analog circuits. Therefore exist necessity to develop new ultra-low noise power supplies, which can cooperate with specified amplifiers and preamplifiers. It is very common that professional power supplies are very expensive and still have disadvantages. This paper proposes simple and inexpensive solution, which fulfill specific...
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Performance of Noise Map Service Working in Cloud Computing Environment
PublicationIn the paper a noise map service designated for the user interested in environmental noise subject is presented. It is based on cloud computing. Noise prediction algorithm and source model, developed for creating acoustic maps, are working in cloud computing environment. In the study issues related to noise modeling of sound propagation in urban spaces are discussed with a special focus on road noise. Examples of results obtained...
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Quality assessment of ZnO-based varistors by 1/f noise
PublicationNoise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented....
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Two-stage method of impulsive noise detection for audio signals
PublicationPrzedstawiono nowa dwuetapową metodę detekcji zakłóceń impulsowych opartą na analizie funkcji gęstości rozkładu prawdopodobieństwa zakłóconego sygnału. Opisano algorytm określania poziomu wyzwalania detektora progowego.
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Piece-wise constant approximation method of identification of RTS noise
PublicationPrzedstawiono nową metodę wydzielania szumów RTS z całkowitych szumów przyrządów półprzewodnikowych. Metoda ta oparta jest na aproksymacji liniowo odcinkowej przebiegu szumowego.Przedstawiono wyniki zastosowania tej metody do wydzielenia dwupoziomowego szumu RTS z szumu przyrządu półprzewodnikowego.
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Fast clutter cancellation for noise radars via waveform design
PublicationCanceling clutter is an important, but very expensive part of signal processing in noise radars. It is shown that considerable improvements can be made to a simple least squares canceler if minor constraints are imposed onto noise waveform. Using a combination of FPGA and CPU, the proposed scheme is capable of canceling both stationary clutter and moving targets in real-time, even for high sampling rates.
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New approach to railway noise modeling employing Genetic Algorithms
PublicationMain 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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Shipping Low Frequency Noise and Its Propagation in Shallow Water
PublicationOne of the most significant factor influencing acoustical climate of the sea is underwater noise generated by moving ships. If the considered sea area has features of the shallow water, namely the wave frequency fulfils relation f < 10c/h, where c denotes phase speed of sound, and h is depths of the sea, then in certain distance from the wave source specific image of sound pressure distribution in the mean of wave modes appears....
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Cheap Cancellation of Strong Echoes for Digital Passive and Noise Radars
PublicationThe problem of cancellation of strong, potentially nonstationary,echoes in noise radars and passive radars utilizing digitaltransmissions is considered. The proposed solution is a multi-stage procedure.Initial clutter estimates, obtained using the least mean squares(LMS) algorithm, are refined using specially designed filters, "matched"to spectral densities of targets and clutter. When the postprocessing filtersare noncausal, the...
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Some aspects of noise generated by a small ship in the shallow sea
PublicationThe 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...
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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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DEVELOPMENT OF A COUPLED NUMERICAL AND EXPERIMENTAL APPROACH TO HYDRODYNAMIC NOISE ESTIMATION
PublicationThe 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...
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Selective monitoring of noise emitted by vehicles involved in road traffic
PublicationAn 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...
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Traffic Noise Analysis Applied to Automatic Vehicle Counting and Classification
PublicationProblems 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...
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Generation-recombination and 1/f noise in carbon nanotube networks
PublicationThe low-frequency noise is of special interest for carbon nanotubes devices, which are building blocks for a variety of sensors, including radio frequency and terahertz detectors. We studied noise in as-fabricated and aged carbon nanotube networks (CNNs) field-effect transistors. Contrary to the majority of previous publications, as-fabricated devices demonstrated the superposition of generation-recombination (GR) and 1/f noise...
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Evaluation of Lombard Speech Models in the Context of Speech in Noise Enhancement
PublicationThe Lombard effect is one of the most well-known effects of noise on speech production. Speech with the Lombard effect is more easily recognizable in noisy environments than normal natural speech. Our previous investigations showed that speech synthesis models might retain Lombard-effect characteristics. In this study, we investigate several speech models, such as harmonic, source-filter, and sinusoidal, applied to Lombard speech...
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Resistance Noise Higher-Order Spectrums in Nanoparticle Gas Sensors.
PublicationPrzedstawiono 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.
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Applications of electrochemical noise technique in stress corrosion cracking diagnosis
PublicationW 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...
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Noise Analysis and Optimization of Continuous-Time OTA-C Filters
PublicationW 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...
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Analysis and Optimization of Noise in Continuous-Time OTA-C Filters
PublicationW 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...
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Temperature influence on tire/road noise evaluated by the drum method
PublicationAmbient air and road surface temperatures substantially affect the road vehicle noise emission. The temperature influence on tire/road noise depends mainly on tire-road combination. It is different for dense and porous pavements, for bituminous and cement ones. It differs also depending on tires. The correction procedures for temperature effect are still under consideration and preparation. Laboratory experiment was prepared to...
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Reduction of noise and rolling resistance by horizontal grinding of asphalt pavements
PublicationGrinding of cement concrete pavements to reduce unevenness and noise is common since a long time. Grinding is then made with wheels equipped with diamond blades rotating in the vertical plane. This creates narrow vertical/longitudinal grooves in the pavement. It is not applied to asphalt pavements. In this paper an alternative type of grinding is studied. In this case plates with diamond heads rotate in the same plane as the pavement,...
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Noise profiling for speech enhancement employing machine learning models
PublicationThis 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...
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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...
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Investigation of noises in the EPN weekly time series
PublicationThe constantly growing needs of permanent stati ons’ velocities users cause their stability level to increase. To this research we included more than 150 stations located across Europe operating within the EUREF Permanent Network (EPN) w ith weekly changes in the ITRF2005 reference frame. The obvious long-range dependencies in the stochastic part of GPS time series were p roven by Ljung-Box...
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Review and comparison of smoothing algorithms for one-dimensional data noise reduction
PublicationThe 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....