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Investigation of the temperature modulation parameters on semiconductor gas sensor response
PublicationIn this work we present the results of the investigation of the sensing properties of semiconductor gas sensors with a sinusoidally modulated temperature in the presence of synthetic air (SA) and three volatile air pollutants, i.e. NH3, NO2 and SO2. The measurements were performed for different average sensor heater temperatures and the amplitude of the modulation signal. In addition, the extraction of features from the sensor...
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Design of OFDM-based radio communication systems for coast-to-sea and coast-to-air propagation environments
PublicationIn the paper the study of radio communication system design process for systems based on OFDM transmission is considered. The signal propagation model for 1.4 GHz frequency band is discussed, and the study of signal propagation characteristics, important from the point of view of OFDM system design, is presented. The methodology of OFDM interface design is proposed and some characteristics of the OFDM-based radio communication...
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ECG measurement in the bathtub - drl on one side of the bathtub, the other side of the bathtub is grounded and the system ground is grounded- men
Open Research DataThe measurement data shows the measurement of the ECG signal in water in the bathtub. The data includes the measurement time, the reference ECG signal from the chest, and the ECG signal measured by electrodes placed in the bathtub without contact with the human body. Using the presented data, it is possible to estimate the optimal arrangement of measuring...
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Instantaneous complex frequency for pipeline pitch estimation
PublicationIn the paper a pipeline algorithm for estimating the pitch of speech signal is proposed. The algorithm uses instantaneous complex frequencies estimated for four waveforms obtained by filtering the original speech signal through four bandpass complex Hilbert filters. The imaginary parts of ICFs from each channel give four candidates for pitch estimates. The decision regarding the final estimate is made based on the real parts of...
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Superresolution algorithm to video surveillance system
PublicationAn application of a multiframe SR (superresolution) algorithm applied to video monitoring is described. The video signal generated by various types of video cameras with different parameters and signal distortions which may be very problematic for superresolution algorithms. The paper focuses on disadvantages in video signal which occur in video surveillance systems. Especially motion estimation and its influence on superresolution...
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Comparison of Acoustic and Visual Voice Activity Detection for Noisy Speech Recognition
PublicationThe problem of accurate differentiating between the speaker utterance and the noise parts in a speech signal is considered. The influence of utilizing a voice activity detection in speech signals on the accuracy of the automatic speech recognition (ASR) system is presented. The examined methods of voice activity detection are based on acoustic and visual modalities. The problem of detecting the voice activity in clean and noisy...
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Application of thin diamond films in low-coherence fiber-optic Fabry Pérot displacement sensor
PublicationThe novel fiber-optic low coherence sensor with thin diamond films is demonstrated. The undoped and boron-doped diamond films were elaborated by the use of the microwave plasma enhanced chemical vapor deposition (μPE CVD) system. The optical signal from the Fabry–Pérot cavity made with the application of those thin films is sensitive to displacement. The sensor characterization was made in the range of 0–600 μm. The measurements...
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Rzadka reprezentacja sygnału niestacjonarnego w technice oszczędnego próbkowania
PublicationPrzedstawiono zastosowanie techniki oszczędnego próbkowania do rekonstrukcji sygnału niestacjonarnego na podstawie skompresowanych próbek w dziedzinie czas-częstotliwość. Zastosowano nadmiarowy algorytm z różnymi słownikami aby znaleźć rzadką reprezentację sygnału. Wyniki symulacji potwierdzają, że zastosowanie oszczędnego próbkowania pozwala na rekonstrukcję sygnału niestacjonarnego z małej liczby losowo pobranych próbek, z niewielką...
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Fully Adaptive Savitzky-Golay Type Smoothers
PublicationThe problem of adaptive signal smoothing is consid-ered and solved using the weighted basis function approach. Inthe special case of polynomial basis and uniform weighting theproposed method reduces down to the celebrated Savitzky-Golaysmoother. Data adaptiveness is achieved via parallel estimation.It is shown that for the polynomial and harmonic bases andcosinusoidal weighting sequences, the competing signal estimatescan be computed...
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Ultrasonic spectroscopy of silicon single crystal
PublicationSpecimens of Si single crystals with different crystal orientation [100] and [110] were studied by the electro-ultrasonic spectroscopy (EUS) and Resonant Ultrasonic Spectroscopy (RUS). A silicon single crystal is an anisotropic crystal, so its properties are different in different directions in the material relative to the crystal orientation. EUS is based on interaction of two signals: electric AC signal and ultrasonic signal,...
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Audio codec employing frequency-derived tonality measure
PublicationA transform codec employing efficient algorithm for detection of spectral tonal components is presented. The tonality measure used in MPEG psychoacoustic model is replaced with the method providing adequate tonality estimates even if the tonal components are deeply frequency modulated. The reliability of hearing threshold estimated using psychoacoustic model with standardized tonality measure and the proposed one is investigated...
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Implementation of DIFAR Processing in ASW Dipping Sonar
PublicationThis paper presents the implementation of the signal processing algorithm used by buoy DIFAR (Directional Frequency Analysis and Recording), that is fully operational on Polish Navy anti-submarine warfare (ASW) helicopters and ships, applied to dipping sonars for detection and tracking of submarines. The development of the DSP algorithms was a part of the modernization of sonars conducted at the Gdansk University of Technology....
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Atomic Force Microscope data post-processing algorithm for higher harmonics imaging
PublicationPrevious works have proved that higher harmonics topography imaging using atomic force microscope (AFM) can significantly enhanced its measurement capabilities. Integrated tools dedicated to most of microscopes allow to visualize the investigated surface only by one selected harmonic. Because of the different characteristics of a sample, scanning tip and the environment, appropriate harmonic selection is time consuming and requires...
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Quality Evaluation of Novel DTD Algorithm Based on Audio Watermarking
PublicationEcho cancellers typically employ a doubletalk detection (DTD) algorithm in order to keep the adaptive filter from diverging in the presence of near-end speech signal or other disruptive sounds in the microphone signal. A novel doubletalk detection algorithm based on techniques similar to those used for audio signal watermarking was introduced by the authors. The application of the described DTD algorithm within acoustic echo cancellation...
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A New Coupler Concept for Contactless High-Speed Data Transmission Monitoring
PublicationThis paper presents a new concept of a couplerthat can be applied to high-speed data transmission contactlessmeasurements. The proposed approach is dedicated for differentialsignal transmission monitoring in microstrip coupled lineson printed circuit boards (PCBs). The coupler, produced on aseparate PCB, is overlayed on the transmission line with thedifferential signal and delivers decoupled differential signal tothe main measurement...
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Position Estimation in Corridors Along the Coupled Mode of Radiating Cables
PublicationRadiating cables are mostly used to provide radio communication in tunnels or corridors, but they can also be used to estimate the position of a mobile terminal along the cable. In this paper, a measuring receiver’s position was estimated by measuring the difference in the direct signal’s reception time, which was generated by a transmitter connected to one end of the radiating cable, and the delayed signal retransmitted from another...
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Compressive Sensing Approach to Harmonics Detection in the Ship Electrical Network
PublicationThe contribution of this paper is to show the opportunities for using the compressive sensing (CS) technique for detecting harmonics in a frequency sparse signal. The signal in a ship’s electrical network, polluted by harmonic distortions, can be modeled as a superposition of a small number of sinusoids and the discrete Fourier transform (DFT) basis forms its sparse domain. According to the theory of CS, a signal may be reconstructed...
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Janusz Nieznański prof. dr hab. inż.
PeopleJanusz Nieznański born in 1957 in Gdańsk. He received the M.Sc. degree in 1981, the Ph.D. degree in 1990, and the D.Sc. (‘habilitation’) degree in 1999, all from the Gdańsk University of Technology. Since 1981 he has been with the above university, where he is currently Professor of Electrical Engineering. His research and teaching interests include control, diagnostics, modeling and simulation of power electronic converters and...
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Multifrequency self-optimizing narrowband interference canceller
PublicationThe problem of cancellation of a nonstationary sinusoidal interference, acting at the output of a linear stable plant, is considered. It is assumed that disturbance is a multifrequency narrowband signal, and that system output is contaminated with wideband noise. It is not assumed that the reference signal is available. Two disturbance cancelling schemes are proposed, one for disturbances with unrelated frequency components, and...
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Analysis of Lombard speech using parameterization and the objective quality indicators in noise conditions
PublicationThe aim of the work is to analyze Lombard speech effect in recordings and then modify the speech signal in order to obtain an increase in the improvement of objective speech quality indicators after mixing the useful signal with noise or with an interfering signal. The modifications made to the signal are based on the characteristics of the Lombard speech, and in particular on the effect of increasing the fundamental frequency...
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POPRAWA OBIEKTYWNYCH WSKAŹNIKÓW JAKOŚCI MOWY W WARUNKACH HAŁASU
PublicationCelem pracy jest modyfikacja sygnału mowy, aby uzyskać zwiększenie poprawy obiektywnych wskaźników jakości mowy po zmiksowaniu sygnału użytecznego z szumem bądź z sygnałem zakłócającym. Wykonane modyfikacje sygnału bazują na cechach mowy lombardzkiej, a w szczególności na efekcie podniesienia częstotliwości podstawowej F0. Sesja nagraniowa obejmowała zestawy słów i zdań w języku polskim, nagrane w warunkach ciszy, jak również w...
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Estimation of Coherence Bandwidth for Underwater Acoustic Communication Channel
PublicationA shallow underwater acoustic communication channel is characterized by strong multipath propagation. The signal reaching the receiver consists of a direct waveform and a number of its delayed and suppressed replica. A significant time dispersion of the transmitted signal and selective fading of its spectrum are observed. Coherence bandwidth defines maximal bandwidth, wherein the channel amplitude characteristic remains constant...
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Investigating Feature Spaces for Isolated Word Recognition
PublicationMuch attention is given by researchers to the speech processing task in automatic speech recognition (ASR) over the past decades. The study addresses the issue related to the investigation of the appropriateness of a two-dimensional representation of speech feature spaces for speech recognition tasks based on deep learning techniques. The approach combines Convolutional Neural Networks (CNNs) and timefrequency signal representation...
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A body position influence on ECG derived respiration
PublicationAn influence of a human body position on ECG derived respiration (EDR) signal is presented in the paper. Examinations were performed during deep, suspended and normal breathing for eight people in four different body positions. EDR and thoracic impedance signals were compared using correlation and standard deviation coefficients. Obtained results have shown that it is possible to monitor breath activity of people being in different...
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Properties and interpretation of Instantaneous Complex Frequency
PublicationThe concept of Instantaneous Complex Frequency (ICF) was first defined by Lindon and developed mainly in works of two authors S. Hahn and M. Rojewski. Although it is not widely used in signal analysis, ICF was already used as a complex signal representation in the verification of handwritten signatures, pitch estimation, symbol timing recovery in PSK receiver and in detection of anomalies in data transmission. It should be noted,...
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From the multiple frequency tracker to the multiple frequency smoother
PublicationThe problem of extraction/elimination of nonstationary sinusoidalsignals from noisy measurements is considered. This problem is usually solved using adaptive notch filtering (ANF)algorithms. It is shown that the accuracy of frequency estimates can be significantly increased if the results obtained from ANF are backward-time filtered by an appropriately designed lowpass filter. The resulting adaptive notch smoothing (ANS)algorithm...
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A new approach to active noise and vibration control - [Part II: unknown frequency case]
PublicationThis paper presents a new approach to rejection of complex-valued sinusoidal disturbances acting at the output of a discrete-time stable linear plant with unknown and possibly timevarying dynamics. It is assumed that both the instantaneous frequency of the sinusoidal disturbance and its amplitude may be slowly varying with time and that the output signal is contaminated with wideband measurement noise. It is not assumed that a...
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Human voice modification using instantaneous complex frequency
PublicationThe paper presents the possibilities of changing human voice by modifying instantaneous complex frequency (ICF) of the speech signal. The proposed method provides a flexible way of altering voice without the necessity of finding fundamental frequency and formants' positions or detecting voiced and unvoiced fragments of speech. The algorithm is simple and fast. Apart from ICF it uses signal factorization into two factors: one fully...
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Multichannel Human Body Communication
PublicationHuman Body Communication is an attractive alternative for traditional wireless communication (Bluetooth, ZigBee) in case of Body Sensor Networks. Low power, high data rates and data security makes it ideal solution for medical applications. In this paper, signal attenuation for different frequencies, using FR4 electrodes, has been investigated. Performance of single and multichannel transmission with frequency modulation of analog...
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Analiza stanu nawierzchni i klas pojazdów na podstawie parametrów ekstrahowanych z sygnału fonicznego
PublicationCelem badań jest poszukiwanie parametrów wektora cech ekstrahowanego z sygnału fonicznego w kontekście automatycznego rozpoznawania stanu nawierzchni jezdni oraz typu pojazdów. W pierwszej kolejności przedstawiono wpływ warunków pogodowych na charakterystykę widmową sygnału fonicznego rejestrowanego przy przejeżdżających pojazdach. Następnie, dokonano parametryzacji sygnału fonicznego oraz przeprowadzano analizę korelacyjną w celu...
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On adaptive covariance and spectrum estimation of locally stationary multivariate processes
PublicationWhen estimating the correlation/spectral structure of a locally stationary process, one has to make two important decisions. First, one should choose the so-called estimation bandwidth, inversely proportional to the effective width of the local analysis window, in the way that complies with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive...
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Photoplethysmographic Time-Domain Heart Rate Measurement Algorithm for Resource-Constrained Wearable Devices and its Implementation
PublicationThis paper presents an algorithm for the measurement of the human heart rate, using photoplethysmography (PPG), i.e., the detection of the light at the skin surface. The signal from the PPG sensor is processed in time-domain; the peaks in the preprocessed and conditioned PPG waveform are detected by using a peak detection algorithm to find the heart rate in real time. Apart from the PPG sensor, the accelerometer is also used to...
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Methodology and technology for the polymodal allophonic speech transcription
PublicationA method for automatic audiovisual transcription of speech employing: acoustic and visual speech representations is developed. It adopts a combining of audio and visual modalities, which provide a synergy effect in terms of speech recognition accuracy. To establish a robust solution, basic research concerning the relation between the allophonic variation of speech, i.e. the changes in the articulatory setting of speech organs for...
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Methodology and technology for the polymodal allophonic speech transcription
PublicationA method for automatic audiovisual transcription of speech employing: acoustic, electromagnetical articulography and visual speech representations is developed. It adopts a combining of audio and visual modalities, which provide a synergy effect in terms of speech recognition accuracy. To establish a robust solution, basic research concerning the relation between the allophonic variation of speech, i.e., the changes in the articulatory...
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The conducted immunity test of a power supply unit in accordance with EMC standards
Open Research DataThe dataset presents a result of measurements that are a part of immunity tests to conducted disturbances, induced by radio-frequency fields. The immunity tests were carried out on the mains cable of the DF1723003TC NDN power supply. Tests of immunity of electronic systems to conducted disturbances in the frequency range from 150 kHz to 230 MHz are...
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Application of IR UWB Spectrum Shaping to IEEE 802.15.4a Standard
PublicationCoexistence of existing narrowband systems and new ultra wideband devices in the same frequency range requires using some interference mitigation techniques, for example based on spectrum shaping. This paper presents efficiency of impulse radio spectrum shaping methods, applied to IEEE 802.15.4a UWB alternate physical layer signals. Basic parameters of 802.15.4a signal structure and outline of proposed spectrum shaping methods...
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Design, Realization and Measurements of Enhanced Performance 2.4 GHz ESPAR Antenna for Localization in Wireless Sensor Networks
PublicationThis paper presents the design, realization and measurements of an Electronically Steerable Parasitic Array Radiator (ESPAR) antenna with enhanced performance of estimating the incoming signal direction. Designed antenna is dedicated for 2.4 GHz ISM applications with emphasis on Wireless Sensor Networks (WSN). Proposed antenna provides different radiation patterns by proper configuration of the parasitic elements. Thus, several...
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Using phase of short-term Fourier transform for evaluation of spectrogram performance
PublicationThe concept of spectrogram performance evaluation which exploits information on phase of short-term Fourier transform (STFT) is presented. A spectrograph which is time-frequency analyzing tool, is compared to a filter bank that demultiplexes a signal. Local group delay (LGD) and channelized instantaneous frequency (CIF) is obtained for each filtered component signal. In presented solution the performance is evaluated using so-called...
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New results on estimation bandwidth adaptation
PublicationThe problem of identification of a nonstationary autoregressive signal using non-causal estimation schemes is considered. Noncausal estimators can be used in applications that are not time-critical, i.e., do not require real-time processing. A new adaptive estimation bandwidth selection rule based on evaluation of pseudoprediction errors is proposed, allowing one to adjust tracking characteristics of noncausal estimators to unknown...
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The conducted immunity test of a power supply unit in the frequency range from 19 MHz to 26 MHz for the RF voltage level of 3 V
Open Research DataThe dataset presents a result of measurements that are a part of immunity tests to conducted disturbances, induced by radio-frequency fields. The immunity tests were carried out on the mains cable of the DF1723003TC NDN power supply unit. Tests of immunity of electronic systems to conducted disturbances in the frequency range from 19 MHz to 26 MHz were...
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The conducted immunity test of a power supply unit in the frequency range from 19 MHz to 26 MHz for the RF voltage level of 1 V
Open Research DataThe dataset presents a result of measurements that are a part of immunity tests to conducted disturbances, induced by radio-frequency fields. The immunity tests were carried out on the mains cable of the DF1723003TC NDN power supply unit. Tests of immunity of electronic systems to conducted disturbances in the frequency range from 19 MHz to 26 MHz were...
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The conducted immunity test of a power supply unit in the frequency range from 19 MHz to 26 MHz for the RF voltage level of 10 V
Open Research DataThe dataset presents a result of measurements that are a part of immunity tests to conducted disturbances, induced by radio-frequency fields. The immunity tests were carried out on the mains cable of the DF1723003TC NDN power supply unit. Tests of immunity of electronic systems to conducted disturbances in the frequency range from 19 MHz to 26 MHz were...
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Applications of Raman spectroscopy for detection of selected substances in tissues
PublicationThis dissertation explores the applications of Raman spectroscopy for biological tissue analysis. Basics of Raman and surface-enhanced Raman spectroscopy (SERS) are described, along with an analysis of the literature on biodetection and non-invasive blood analysis with emphasis on glucose detection. Instrumentation for Raman measurements is described. The sources of noise and interferences occurring in biological tissue measurements...
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An Instantaneous Engine Speed Estimation Method Using Multiple Matching Synchrosqueezing Transform
PublicationInstantaneous rotational speed measurement of the engine is crucial in routine inspection and maintenance of an automobile engine. Since the contact measurement of rotational speed is not always available, the vibration measurement has been used for noncontact rotational speed estimation methods. Unfortunately, the accuracy of the noncontact estimation methods by analyzing engine vibration frequency is not satisfactory due to the...
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Implementation of the digital receiver in multibeam long-range sonar
PublicationThe article presents the implementation of a digital receiver in multibeam long - range sonar. Developed by the authors of the article, the implementation was part of sonar modernisation on large Polish Navy ships. The article explains the structure of the receiver, its design details and requirements affecting the architecture. The technical solutions regarding the equipment and signal processing algorithms for determining receiving...
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Selected properties and parameters of radio channel impulse response estimation in ISM 2.4 GHz band
PublicationThe article presents experimental research indicating that the impulse response of the communication channel, determined in practice, are not of an universal character, but only represent its approximate value for the frequency on which this measurement was made. Phases for each of the replicas of the measurement signal were determined during the analysis of the received signals in the baseband. Phase changes of individual replicas...
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Residence time distribution in rapid multiphase reactors
PublicationResidence time distribution (RTD) provides information about average hydraulic residence time and the distribution of material in the reactor. A method for determining RTD for reactors with very short hydraulic residence times is deconvolution based on extraction of real RTD by the analysis of a non-ideal input signal. The mean residence time and dispersion were determined for the spinning fluids reactor (SFR). For the first time...
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The Influence of the Radio Channel on Precision of Position Estimation of the User Terminal Using the NB-IoT Radio Interface
PublicationIn the article the method of user terminal position estimation using the broadcast signals transmitted in the downlink of the NB-IoT interface was presented, including the analysis of the radio channel influence on precision of position estimation as well as the eNodeB (Evolved Node B) synchronization. The practical ability to estimate the position in the test area has been verified in the laboratory conditions, using the reference...
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Radioisotope measurement of selected parameters of liquid-gas flow using single detector system
PublicationTo determine the parameters of two-phase flows using radioisotopes, usually two detectors are used. Knowing the distance between them, the velocity of the dispersed phase is calculated based on time delay estimation. Such a measurement system requires the use of two gamma-ray sealed sources. But in some situations it is also possible to determine velocity of dispersed phase using only one scintillation probe and one gamma-ray source....
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An Attempt to Create Speech Synthesis Model That Retains Lombard Effect Characteristics
PublicationThe speech with the Lombard effect has been extensively studied in the context of speech recognition or speech enhancement. However, few studies have investigated the Lombard effect in the context of speech synthesis. The aim of this paper is to create a mathematical model that allows for retaining the Lombard effect. These models could be used as a basis of a formant speech synthesizer. The proposed models are based on dividing...