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Search results for: DISTORTION COMPENSATION
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Communication Platform for Evaluation of Transmitted Speech Quality
PublicationA voice communication system designed and implemented is described. The purpose of the presented platform was to enable a series of experiments related to the quality assessment of algorithms used in the coding and transmitting of speech. The system is equipped with tools for recording signals at each stage of processing, making it possible to subject them to subjective assessments by listening tests or, objective evaluation employing...
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Próba oceny efektów projektowania układów geometrycznych toru z wykorzystaniem komercyjnych programów komputerowych
PublicationW pracy podjęto kwestię dokładności uzyskiwanej w projektowaniu układów geometrycznych toru z wykorzystaniem komercyjnych programów komputerowych typu CAD. Opisano w sposób ogólny funkcjonowanie wybranego programu. Do celów weryfikacji wykorzystano własną, analityczną metodę projektowania układów torowych. W analizie porównawczej rzędnych poziomych rozpatrzono trzy warianty układu geometrycznego zawierającego łuk koszowy z trzema...
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APPLICABILITY OF INLET AIR FOGGING TO MARINE GAS TURBINE
PublicationThe dependency of marine gas turbine on the ambient temperature leads to a decrease of the gas turbine power output in arid areas. Very often gas turbine power output demand is high and the power margins originally designed into the driver , has been exhausted. In such circumstances the inlet air fogging is an effective compensation of gas turbine power. In this paper an analysis of inlet air fogging applicability to marine gas...
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Generalized Chebyshev Bandpass Filters With Frequency-Dependent Couplings Based on Stubs
PublicationThis paper presents an accurate synthesis method for inline and cross-coupled generalized Chebyshev bandpass filters with frequency-dependent couplings implemented via open and short stubs. The technique involves the synthesis of a lumped-element prototy pe in the form of a coupling matrix with a frequency-dependent term and the conversion of this prototype to a distributed-element mode l composed of sections of TEM lines. This...
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Thermodynamic Studies of Interactions between Sertraline Hydrochloride and Randomly Methylated β-Cyclodextrin Molecules Supported by Circular Dichroism Spectroscopy and Molecular Docking Results
PublicationThe interaction between sertraline hydrochloride (SRT) and randomly methylated β-cyclodextrin (RM β CD) molecules have been investigated at 298.15 K under atmospheric pressure. The method used—Isothermal Titration Calorimetry (ITC) enabled to determine values of the thermodynamic functions like the enthalpy (DH), the entropy (DS) and the Gibbs free energy (DG) of binding for the examined system. Moreover, the stoichiometry coefficient...
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A Power-Efficient Digital Technique for Gain and Offset Correction in Slope ADCs
PublicationIn this brief, a power-efficient digital technique for gain and offset correction in slope analog-to-digital converters (ADCs) has been proposed. The technique is especially useful for imaging arrays with massively parallel image acquisition where simultaneous compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. The presented approach is based on stopping the ADC clock by...
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WARUNKI REZONANSOWE W WĘŹLE Z KOMPENSATOREM SVC
PublicationInstalowanie kompensatorów statycznych w sieciach rozdzielczych i przesyłowych służy poprawie profili napięciowych. Kompensatory jako źródła mocy biernej zwiększają stabilność napięciową systemu. Pozwalają także na szybszą odbudowę systemu w przypadku awarii napięciowej. W artykule zaprezentowano wpływ struktury i wysterowania układu SVC na zmianę impedancji w układzie zasilania. Ma to bezpośredni wpływ na częstotliwości, przy...
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Erroneous GNSS Strain Rate Patterns and their Application to Investigate the Tectonic Credibility of GNSS Velocities
PublicationThe paper concerns investigation of the credibility of tectonic interpretation of GNSS strain rates. The analysis was focused on stable regions, where the crustal deformations are small and the reliability of GNSS velocities is questionable. We are showing how the unreliable motion of stations affects calculated strains around them. We expressed distribution of local principal strains by a sinusoidal function and used them to investigate...
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High-Resolution, Broad-Range Detection Setup for Polarimetric Optical Fiber Sensors
PublicationA common-path polarization interferometer using a Wollaston prism and an area detector for the measurement of retardation or optical path difference is presented. Employing a moderate-resolution 1280 by 1024 pixel monochrome camera, it offers a measurement range of approximately 780 radians at 830 nm and 1350 radians at 515 nm while maintaining a high measurement resolution. Retardation introduced by a zero-order waveplate or a...
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Effect of adhesive compliance in the assessment of soft adhesives with the wedge test
PublicationWedge tests are usually analysed assuming that the free, unbonded members may be treated as encastré cantilever beams. However, if the adhesive layer is sufficiently flexible (e.g., due to low elastic modulus), then significant strain in the bonded region may occur and lead to modification of the behaviour outside this region. Using in conjunction a sensitive strain gauge method on asymmetric wedge tests and a mathematical analysis...
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Current divider-based nanosecond high current pulse measuring systems
PublicationThis paper presents the analysis of the new approach to the measurement methodology of significant values (in order of hundreds of kA) and huge steepness (in order of MA/μs) current pulses based on current dividers along with a comparison of the various types transducers suitability in measuring systems with such extreme parameters. Such dividers are used to extend the measurement ranges of current transducers with limited current...
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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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Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter
PublicationIn this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely...
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Features of Nonlinear Sound Propagation in Vibrationally Excited Gases
PublicationWeakly nonlinear sound propagation in a gas where molecular vibrational relaxation takes place is studied. New equations which govern the sound in media where the irreversible relaxation may take place are derived and discussed. Their form depends on the regime of excitation of oscillatory degrees of freedom, equilibrium (reversible) or non-equilibrium (irreversible), and on the comparative frequency of the sound in relation to...
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The luminescence study of Ga1.98–xAlxO3:0.02Cr3+ coumpounds.
Open Research DataA chemical and mechanical pressure-induced photoluminescence tuning method was developed through structural evolution and hydrostatic pressure involving phase transition. A series of Ga1.98−xAlxO3:0.02Cr3+ phosphors were synthesized by collaborators from National Taiwan University. Structural evolution reveals a crystal phase change with the incorporation...
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A new approach to active noise and vibration control - [Part I: the known 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 dynamics. It is assumed that the frequency of the sinusoidal disturbance is known, and that the output signal is contaminated with wideband measurement noise. The disturbance rejection control rule is first derived and analyzed for a nominal plant model, different from...
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Wind Turbines Modeling as the Tool for Developing Algorithms of Processing their Video Recordings
PublicationIn the real world, many factors exist disturbing observation of the examined phenomena and causing various noises and distortions in recorded signals. It very often makes it difficult or even impossible to optimize various signal processing algorithms, through finding appropriate parameters. In this paper, we show an application, that retrieves wind turbine rotor speed from recorded video. Next, we describe the process of reduction...
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Wind Turbines Modeling as the Tool for Developing Algorithms of Processing their Video Recordings
PublicationIn the real world, many factors exist disturbing observation of the examined phenomena and causing various noises and distortions in recorded signals. It very often makes it difficult or even impossible to optimize various signal processing algorithms, through finding appropriate parameters. In this paper, we show an application, that retrieves wind turbine rotor speed from recorded video. Next, we describe the process of reduction...
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Application of OFDM technique to underwater acoustic data transmission
PublicationPerformances of underwater acoustic communication (UAC) digital systems are strongly related to specific transmission properties of the underwater channel. Depending on the characteristics of the channel, an architecture and modulation techniques are usually implemented that are known as reliable solutions for data transmission in difficult radio channels. The OFDM technique seems to be the most promising nowadays. The parameters...
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Current harmonic controller in multiple reference frames for series active power filter integrated with 18-pulse diode rectifier
PublicationThe paper presents the control system and selected results of experimental tests of the AC/DC power converter consisting of an 18-pulse diode rectifier based on coupled reactors and a serial active power filter. Proportional integral controllers with decoupling components are implemented in multiple reference frames for selective line current harmonic suppression. The regulator is provided with a backtracking anti-windup mechanism...
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Isolation and structure of a covalent cross-link adduct between mitomycin C and DNA
PublicationA DNA cross-link adduct of the antitumor agent mitomycin C (MC) to DNA has been isolated and characterized; the results provide direct proof for bifunctional alkylation of DNA by MC. Exposure of MC to Micrococcus luteus DNA under reductive conditions and subsequent nuclease digestion yielded adducts formed between MC and deoxyguanosine residues. In addition to the two known monoadducts, a bisadduct was obtained. Reductive MC activation...
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Multiple output differential OTA with linearizing bulk-driven active-error feedback loop for continuous-time filter applications
PublicationA CMOS circuit realization of a highly linear multiple-output differential operational transconductance amplifier (OTA) has been proposed. The presented approach exploits a differential pair as an input stage with both the gate and the bulk terminals as signal ports. For the proposed OTA, improved linearity is obtained by means of the active-error feedback loop operating at the bulk terminals of the input stage. SPICE simulations...
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Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublicationA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
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A low-voltage CMOS negative impedance converter for analogue filtering applications
PublicationLow-voltage high-frequency continuous-time filters are still required in many applications and are the subject of continuing research. There are many techniques to realize integrated filters, including OTA C, Opamp RC and MOSFET-C-Opamp. The latter two show high dynamic range at low supply voltage, but their frequency operating range is usually limited to several megahertz. Transconductance filters are dedicated to higher frequencies....
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Możliwości sterowania mocą bierną elektrowni wiatrowej : Reactive power control methods in wind parks
PublicationReferat poświęcony jest zagadnieniu sterowania mocą bierną w elektrowniach wiatrowych. W pierwszej części referatu opisano tło problemu sterowania mocą bierną w parkach wiatrowych, podano powody, dla których moc bierna powinna podlegać regulacji oraz zarysowano metody, które mogą być do niej użyte. W celu sprawdzenia proponowanych metod kompensacji, zbudowano model matematyczny elektrowni wiatrowej, którego poszczególne elementy...
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Wet H2S corrosion and degradation of pipeline in amine regeneration system
PublicationThe paper presents the results of NDT examinations, metallographic tests and risk assessment of degradation related to corrosion of amine regeneration unit in a desulphurisation system. Intensive corrosion resulting from acid gases environment upon water condensation causes perforation of the pipeline. Detailed analysis reveals cracking related to the mechanism of wet H2S. Hydrogen penetration, resulting from the wet H2S process,...
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On ''cheap smoothing'' opportunities in identification of time-varying systems
PublicationIn certain applications of nonstationary system identification the model-based decisions can be postponed, i.e. executed with a delay. This allows one to incorporate into the identification process not only the currently available information, but also a number of ''future'' data points. The resulting estimation schemes, which involve smoothing, are not causal. Despite the possible performance improvements, the existing smoothing...
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Using wavelet techniques for multibeam sonar bathymetry data compression
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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On the compression of multibeam sonar raw bathymetry data
PublicationMultibeam sonars are widely used in applications like high resolution bathymetry measurements or underwater object imaging. One of the significant problems in multibeam sensing of the marine environment is large amount of data which must be transmitted from the sonar processing unit to an operator station using a limited bit rate channel. For instance, such a situation would be in the case when the multibeam sonar was mounted on...
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Study of the Influence of Heat Convection Coefficient on Predicted Performance of a Large Tilting-Pad Thrust Bearing
PublicationPart of the heat generated by the shearing of the lubricating film during operation of a hydrodynamic bearing is transferred to the bearing components. In the case of the pad, which is usually fully submerged in the lubricating oil, heat is further transferred at the pad free walls to the oil by convection. This mechanism causes a thermal gradient in a pad and, consequently, its thermal deflection. In large hydrodynamic thrust...
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Selective Harmonic Elimination PWM For a Cascaded Multi-level Inverter
PublicationThis paper deals with the selective harmonic elimination pulse width modulation (SHE-PWM) technique. This technique is used for the elimination of selected dominant low order harmonics in the multi-level inverter output voltage. The presence of these harmonics is the essential drawback of such kind of inverters; especially when it is used for the control of different AC drivers. The SHE-PWM is based...
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Effects of Bromine Doping on the Structural Properties and Band Gap of CH3NH3Pb(I1–xBrx)3 Perovskite
PublicationAn experimental and theoretical study is reported to investigate the influence of bromine doping on CH3NH3Pb(I1−xBrx)3 perovskite for Br compositions ranging from x = 0 to x = 0.1, in which the material remains in the tetragonal phase. The experimental band gap is deduced from UV−vis absorption spectroscopy and displays a linear behavior as a function of bromine concentration. Density functional theory calculations are performed...
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The In-Depth Studies of Pulsed UV Laser-Modified TiO2 Nanotubes: The Influence of Geometry, Crystallinity, and Processing Parameters
PublicationThe laser processing of the titania nanotubes has been investigated in terms of morphology, structure, and optical properties of the obtained material. The length of the nanotubes and crystallinity, as well as the atmosphere of the laser treatment, were taken into account. The degree of changes of the initial geometry of nanotubes were checked by means of scanning electron microscopy, which visualizes both the surface and the cross-section....
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Fast bubble dynamics and sizing
PublicationSingle bubble sizing is usually performed by measuring the resonant bubble response using the Dual Frequency Ultrasound Method. However, in practice, the use of millisecond-duration chirp-like waves yields nonlinear distortions of the bubble oscillations. In comparison with the resonant curve obtained under harmonic excitation, it was observed that the bubble dynamic response shifted by up to 20 percent of the resonant frequency...
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Signal filtering method of the fast-varying diesel exhaust gas temperature
PublicationThe paper presents the problem of the impact of external distortions originating on laboratory test stands on the results of measurements of fast-varying diesel exhaust gas temperature. It has been stressed how significant the aspect of the test stand adaptation is during an experiment to ensure the smallest possible impact. This paper, however, focuses on the methods of mathematical processing of a signal recorded during experimental...
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Iterative‐recursive estimation of parameters of regression models with resistance to outliers on practical examples
PublicationHere, identification of processes and systems in the sense of the least sum of absolute values is taken into consideration. The respective absolute value estimators are recognised as exceptionally insensitive to large measurement faults or other defects in the processed data, whereas the classical least squares procedure appears to be completely impractical for processing the data contaminated with such parasitic distortions. Since...
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Disruption of the communication process on the example of ALEP-PL web application
PublicationBy creating a dedicated web service, such as the presented ALEP-PL solution, you can not assume that its users have suffcient knowledge of the energy sector. This application is dedicated to the local energy planning. The ALEP-PL makes it easier to incorporate in the planning of key players in the local energy market. This group of ALEP-PL users represents mainly the ocials of energy companies and specialist offcers. In the paper...
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Broken rotor bar impact on sensorless control of induction machine
PublicationThe aim of the research is analysis of the sensorless control system of induction machine with broken rotor for diagnostic purposes. Increasing popularity of sensorless controlled variable speed drives requires research in area of reliability, range of stable operation, fault symptoms and application of diagnosis methods. T transformation (Cunha et al.,2003) used for conversion of instantaneous rotor currents electrical circuit...
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Periodic Properties of 1D FE Discrete Models in High Frequency Dynamics
PublicationFinite element discrete models of various engineering 1D structures may be considered as structures of certain periodic characteristics. The source of this periodicity comes from the discontinuity of stress/strain field between the elements. This behaviour remains unnoticeable, when low frequency dynamics of these structures is investigated. At high frequency regimes, however, its influence may be strong enough to dominate calculated...
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A concept of Signal Equalization Method Based on Music Genre and the Listener's Room Characteristics
PublicationA research study that investigates the influence of the room acoustics environment on the frequency characteristic of the audio signal playback is presented. First, a novel spectral equalization method of the room acoustic conditions is introduced. On the basis of the frequency response of the room, a system for room acoustics compensation based on eight-band equalizer is proposed. The system settings depend on music genre. In...
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Control of the wind turbine generator
PublicationWind power system consists of two main parts: wind turbine and electrical generator. Wind turbine converts the energy of the flowing air into mechanical energy, next generator converts this energy into electrical energy that is sent to the power system. These two processes should be realized with maximum efficiency and the following requirements for the control system can be formulated: opti-mal wind power conversion, compensation...
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Thermodynamic analysis of the double Brayton cycle with the use of oxy combustion and capture of CO2
PublicationIn this paper, thermodynamic analysis of a proposed innovative double Brayton cycle with the use of oxy combustion and capture of CO2, is presented. For that purpose, the computation flow mechanics (CFM) approach has been developed. The double Brayton cycle (DBC) consists of primary Brayton and secondary inverse Brayton cycle. Inversion means that the role of the compressor and the gas turbine is changed and firstly we have expansion...
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Rain Water: Atmospheric Deposition
PublicationWater is transferred from the atmosphere to the land surface mainly via various forms of atmospheric precipitation; however, the contribution of surface condensation/deposition (e.g., dew, hoar frost, occult precipitation) should not be neglected. Rainwater and liquid deposits (dew, hoar frost, rime) are components of the physical and geographical environment that are easily assimilated and transported. Thus, they are generally...
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Analiza ograniczeń technologicznych systemów lokalizacji inercyjnej
PublicationW artykule opisano kluczowe ograniczenia technologiczne zmniejszające dokładność inercyjnych systemów lokalizacyjnych. Każdy z czynników został przedstawiony w kontekście swego źródła oraz wpływu na proces lokalizacyjny. Dodatkowo w artykule zawarto opis metod kompensacji błędów występujących w procesie lokalizacji inercyjnej. W treści artykułu analizie poddano rozwiązania obecne w systemach lokalizacji inercyjnej dla wolno poruszających...
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A benchmark for particle shape dependence
PublicationParticle shape is a major parameter for the space-filling and strength properties of granular materials. For a systematic investigation of shape effect, a numerical benchmark test was set up within a collaborative group using different numerical methods and particles of various shape characteristics such as elongation, angularity and nonconvexity. Extensive 2D shear simulations were performed in this framework and the shear strength...
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Enhanced Mechanical and Electromechanical Properties of Compositionally Complex Zirconia Zr1–x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2−δ Ceramics
PublicationCompositionally complex oxides (CCOs) or high-entropy oxides (HEOs) are new multi-element oxides with unexplored physical and functional properties. In this work, we report fluorite structure derived compositionally complex zirconia with composition Zr1- x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2-δ (x = 0.1 and 0.2) synthesized in solid-state reaction route and sintered via hot pressing at 1350 °C. We explore the evolution of these oxides'...
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Particle shape dependence in 2D granular media
PublicationParticle shape is a key to the space-filling and strength properties of granular matter. We consider a shape parameter eta describing the degree of distortion from a perfectly spherical shape. Encompassing most specific shape characteristics such as elongation, angularity and non-convexity, eta is a low-order but generic parameter that we used in a numerical benchmark test for a systematic investigation of shape dependence in sheared...
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Robustness in Compressed Neural Networks for Object Detection
PublicationModel compression techniques allow to significantly reduce the computational cost associated with data processing by deep neural networks with only a minor decrease in average accuracy. Simultaneously, reducing the model size may have a large effect on noisy cases or objects belonging to less frequent classes. It is a crucial problem from the perspective of the models' safety, especially for object detection in the autonomous driving...
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Investigation of Noise Threats and Their Impact on Hearing in Selected Schools
PublicationNoise 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...
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Investigation of noise threats and their impact on hearing in selected schools - a pilot study.
PublicationNoise 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...