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Eficient multimode mixed time-frequency domain analysis and optimization of waveguide structures.
PublikacjaW pracy przedstawiona jest pełnofalowa analiza i optymalizacja struktur falowodowych o zadanej topologii. Nieciągłości falowodowe analizowane są z wykorzystaniem metody FDTD-IBC oraz scharakteryzowane uogólnioną macierzą rozproszenia. Efektywność metody zilustrowana jest na przykładzie filtru falowodowego siódmego rzędu.
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Eficient multimode mixed time-frequency domain analysis and optimization of waveguide structures.
PublikacjaW pracy przedstawiona jest pełnofalowa analiza i optymalizacja struktur falowodowych o zadanej topologii. Nieciągłości falowodowe analizowane są z wykorzystaniem metody FDTD-IBC oraz scharakteryzowane uogólnioną macierzą rozproszenia. Efektywność metody zilustrowana jest na przykładzie filtru falowodowego siódmego rzędu.
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Time domain diagnosis of anticorrosion coatings via shape designed measurement signals.
PublikacjaW pracy przedstawiono operującą w dziedzinie czasu metodę diagnostyki pokryć przeciwkorozyjnych, na poziomie identyfikacji parametrów obwodu zastępczego. Metoda jest oparta na pobudzeniu obiektu sygnałem niekonwencjonalnym o projektowanym kształcie i pomiarze odpowiedzi obiektu (tzw. obserwabla) po upływie zadanego czasu T. Parametry obwodu zastępczego są obliczane bezpośrednio z obserwabli na podstawie równań wynikających z topologii...
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Autocovariance based weighting strategy for time series prediction with weighted LS-SVM
PublikacjaPrzedstawiono metodę konstrukcji algorytmów z funkcją jądra, a także dwa algorytmy uzyskane poprzez użycie różnych funkcji straty. Zaproponowano kowariacyjną strategię ważenia algorytmów z kwadratową funkcją straty do problemu predykcji chaotycznych przebiegów czasowych.
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Kalman filtering for 3d real time data visualisation of multibeam sonar records.
PublikacjaPrzedstawiono zastosowanie filtracji Kalmana do korekcji błędów systematycznych występujących w danych pochodzących z systemu wielozwiązkowego. Zaproponowano dwuetapową filtrację danych dla każdego wachlarza danych, która realizowana jest w czasie rzeczywistym. Zaprezentowano rezultaty wizualizacji dna morskiego przed i po filtracji.
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Model reference method and continuous-time system identification in tuning the PID controllers.
PublikacjaW pracy opisano zagadnienie doboru nastaw sterowników PID w układach regulacji automatycznej. W rozważaniach wzięto pod uwagę zarówno klasyczną strukturę jednopętlowego układu sterowania z regulatorem PID umieszczonym w torze głównym, jak też odmienną realizację I-PD z członem całkującym występującym w torze głównym i sterownikiem proporcjonalno-różniczkującym ulokowanym w dodatkowej pętli sprzężenia zwrotnego. Ponieważ powszechnie...
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Application of Cohen's class time-frequency distributions in the Belousov-Zhabotinsky reaction analysis.
PublikacjaW publikacji przedstawiono analizę rejestrów potencjałowych chemicznej reakcji oscylacyjnej Biełousowa-Żabotyńskiego z wykorzystaniem czasowo-częstotliwościowych rozkładów z klasy Cohen'a. Do analizy zastosowano rozkład Wignera-Ville'a, Choi-Williams'a i stożkowy. Opisano zalety oraz wady powyższych metod oraz wnioski o częstotliwościowej kompozycji oscylacji jakie można wyciągnąć na podstawie uzyskanych spektrogramów.
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Entire fracture surface topography parameters for fatigue life assessment of 10H2M steel
PublikacjaIn this paper, the entire fracture surface approach was used to assess an effect of 280,000 h of exploitation under internal pressure of 2.9 MPa and high temperature of 540 °C on the fatigue response of 10H2M (10CrMo9–10) power engineering steel. The mechanical testing was carried out on the hourglass specimens produced from the as-received, unused pipeline and the same material after long-time exploitation. The uniaxial tensile...
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Spectral criterion of infinite fatigue life of beams under asymmetric random loads
PublikacjaRozpatrywana jest trwałość zmęczeniowa belek poddanych stałym i zmiennym obciążeniom osiowym, giętnym i skrętnym o znanych gęstościach widmowych mocy. Założono, że materiał posiada granicę zmęczenia i jest zgodny z modelem Kelvina-Voigta, oraz że składowe naprężenia są stacjonarne, stacjonarnie skorelowane i różniczkowalne w sensie średniokwadratowym. Zdefiniowano naprężenie równoważne i sformułowano kryterium nieograniczonej trwałości...
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Spectral criterion of infinite fatigue life of beams under combined random loads
PublikacjaRozpatrywana jest trwałość zmęczeniowa belek poddanych zmiennym obciążeniom osiowym, giętnym i skrętnym o znanych gęstościach widmowych mocy i zerowych wartościach średnich. Założono, że materiał posiada granicę zmęczenia i jest zgodny z modelem Kelvina-Voigta, oraz że składowe naprężenia są stacjonarne, stacjonarnie skorelowane i różniczkowalne w sensie średniokwadratowym. Zdefiniowano naprężenie równoważne i sformułowano kryterium...
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Ontological Model for Contextual Data Defining Time Series for Emotion Recognition and Analysis
PublikacjaOne of the major challenges facing the field of Affective Computing is the reusability of datasets. Existing affective-related datasets are not consistent with each other, they store a variety of information in different forms, different formats, and the terms used to describe them are not unified. This paper proposes a new ontology, ROAD, as a solution to this problem, by formally describing the datasets and unifying the terms...
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Regularized identification of fast time-varying systems - comparison of two regularization strategies
PublikacjaThe problem of identification of a time-varying FIR system is considered and solved using the local basis function approach. It is shown that the estimation (tracking) results can be improved by means of regularization. Two variants of regularization are proposed and compared: the classical L2 (ridge) regularization and a new, reweighted L2 one. It is shown that the new approach can outperform the classical one and is computationally...
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T1 RELAXATION TIME CALLIBRATION IN MAGNETIC RESONANCE IMAGING USING NANODIAMOND PHANTOMS
PublikacjaMRI is increasingly used in radiation treatment planning because of the excellent soft tissue contrast in the obtained images. It allows more precise definition of the boundaries between healthy tissues and those affected by cancerous lesions. To obtain good image quality, the difference in signal between two types of tissue must be significant despite the noise so it must be properly calibrated. This calibration includes...
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Measurement of expenditure efficiency of Polish cities with county rights in the context of quality of life
PublikacjaThe article is devoted to the measurement of efficiency of overall expenditures. The purpose of the study is to evaluate the efficiency of use of budget resources by local government units in the context of fostering quality of life. The subject of the study is 65 Polish cities with county rights (county status). Calculations were carried out using Data Envelopment Analysis (DEA). The results of analysis confirm the two research...
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Study of Soil Temperature and Moisture Changes in a Physical Model of an Underground Cable Line
PublikacjaThe ampacity of power cables is highly dependent on the thermal resistivity of the soil in which they are laid. The lower it is, the higher this ampacity. The thermal resistivity of the soil decreases as its moisture increases. Therefore, it is preferable that the soil around the cables has high moisture. Unfortunately, the heat generated in heavily loaded cables causes the migration of moisture from the surrounding soil, which...
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FDTD Method for Electromagnetic Simulations in Media Described by Time-Fractional Constitutive Relations
PublikacjaIn this paper, the finite-difference time-domain (FDTD) method is derived for electromagnetic simulations in media described by the time-fractional (TF) constitutive relations. TF Maxwell’s equations are derived based on these constitutive relations and the Grünwald–Letnikov definition of a fractional derivative. Then the FDTD algorithm, which includes memory effects and energy dissipation of the considered media, is introduced....
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Continuous-Time Active-RC Filter Model for Computer-Aided Design and Optimization
PublikacjaW pracy przedstawiono ogólny model filtru aktywnego RC opartego na wzmacniaczach odwracajacych faze. Model analizowany jest przy użyciu równań macierzowych. Podano jawną formułę określającą funkcję przenoszenia filtru w ogólnym przypadku. Przedstawiono rozszerzenia modelu pozwalające uwzgledniać nieidealność wzmacniaczy operacyjnych, w tym skończone wzmocnienie i pasmo przenoszenia oraz niezerową rezystancję wyjściową. Wyprowadzono...
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Crank–Nicolson FDTD Method in Media Described by Time-Fractional Constitutive Relations
PublikacjaIn this contribution, we present the Crank-Nicolson finite-difference time-domain (CN-FDTD) method, implemented for simulations of wave propagation in media described by time-fractional (TF) constitutive relations. That is, the considered constitutive relations involve fractional-order (FO) derivatives based on the Grünwald-Letnikov definition, allowing for description of hereditary properties and memory effects of media and processes....
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Non-classical operational calculus applied to certain linear discrete time-system
PublikacjaW pracy zastosowano nieklasyczny rachunek operatorów do wyznaczania odpowiedzi pewnego dyskretnego układu dynamicznego. Pokazano metodę szczególnie przydatną do wyznaczania odpowiedzi pewnych dyskretnych niestacjonarnych układów dynamicznych, przy których zastosowanie przekształcenia Z sprawia duże trudności.
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Investigations of the circulation effects in the structure using ferrite coupled slot-line section
PublikacjaW artykule przedstawiono badania cyrkulatora zrealizowanego w oparciu o magnesowaną wzdłużnie sekcję ferrytowych szczelinowych linii sprzężonych. Zaproponowane rozwiązanie pozwala na minimalizację rozmiarów układu cyrkulatora oraz na uzyskanie parametrów porównywalnych z dotychczas publikowanymi. W treści artykułu opisano kolejne etapy projektu. Wyniki numeryczne zweryfikowano eksperymentalnie. Pomierzony układ charakteryzował...
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A Compact and Lightweight Microwave Tilt Sensor Based on an SRR-Loaded Microstrip Line
PublikacjaIn this paper, the symmetry property of split ring resonators (SRRs) is exploited to develop a tilt sensor. The sensor is composed of an SRR-loaded microstrip line operating at microwave frequencies. It is shown that the depth of notch in the reflection characteristic of the microstrip is a function of the tilt angle of the SRR. Thus, it can be used for sensing inclination. The sensor benefits from very compact size and light weight....
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Optimally regularized local basis function approach to identification of time-varying systems
PublikacjaAccurate identification of stochastic systems with fast-varying parameters is a challenging task which cannot be accomplished using model-free estimation methods, such as weighted least squares, which assume only that system coefficients can be regarded as locally constant. The current state of the art solutions are based on the assumption that system parameters can be locally approximated by a linear combination of appropriately...
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Price bubbles in commodity market – A single time series and panel data analysis
PublikacjaThis paper examines thirty-five commodities, grouped into three market sectors (energy, metals, agriculture & livestock) in terms of the occurrence of price bubbles. The study was based on monthly data for each commodity separately and, in a panel approach, for selected sectors and for all commodities combined. The GSADF test and its version for panel data – panel GSADF – were used to identify bubbles. The beginning and end of...
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Multiple sound sources localization in real time using acoustic vector sensor
PublikacjaMethod and preliminary results of multiple sound sources localization in real time using the acoustic vector sensor were presented in this study. Direction of arrival (DOA) for considered source was determined based on sound intensity method supported by Fourier analysis. Obtained spectrum components for considered signal allowed to determine the DOA value for the particular frequency independently. The accuracy of the developed...
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Message Inter-Arrival and Inter-Departure Time Distributions in IMS/NGN Architecture
PublikacjaCurrently is it assumed that requirements of the information society for delivering multimedia services will be satisfied by the Next Generation Network (NGN) architecture, which includes elements of the IP Multimedia Subsystem (IMS) solution. In order to guarantee Quality of Service (QoS), NGN has to be appropriately designed and dimensioned. Therefore, proper traffic models should be proposed and applied. This requires determination...
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Investigations of four-port circulator utilizing cylindrical ferrite coupled line junction
PublikacjaW pracy przedstawiono wykorzystanie pojedynczej cylindrycznej sekcji ferrytowych linii sprzężonych do realizacji układu cyrkulatora czterowrotowego. Opisany został proces projektowy sekcji FCL oraz planarnych układów zasilające. Otrzymane z symulacji wyniki zostały zweryfikowane eksperymentalnie.
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Toolgraph Design of Optimal and Feasible Control Strategies for Time-Varying Dynamical Systems
PublikacjaArtykuł prezentuje nową metodę projektowania optymalnych i realizowanych strategii sterowania dla wariantnych procesów dynamicznych. Centralnym ośrodkiem i narzędziem tej metody jest struktura grafu przepływowego reprezentująca istotne właściwości autonomicznej dynamiki danego procesu w przestrzeni czasowo-stanowej, składającej się z elementarnych segmentów. Strukturę tę nazywamy grafem narzędziowym przestrzeni czasowo-stanowej....
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Porous Phantoms Mimicking Tissues—Investigation of Optical Parameters Stability Over Time
PublikacjaOptical phantoms are used to validate optical measurement methods. The stability of their optical parameters over time allows them to be used and stored over long-term periods, while maintaining their optical parameters. The aim of the presented research was to investigate the stability of fabricated porous phantoms, which can be used as a lung phantom in optical system. Measurements were performed in multiple series with an interval...
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Finite-difference time-domain analyses of active cloaking for electrically-large objects
PublikacjaInvisibility cloaking devices constitute a unique and potentially disruptive technology, but only if they can work over broad bandwidths for electrically-large objects. So far, the only known scheme that allows for broadband scattering cancellation from an electrically-large object is based on an active implementation where electric and magnetic sources are deployed over a surface surrounding the object, but whose ‘switching on’...
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Wastes from Agricultural Silage Film Recycling Line as a Potential Polymer Materials
PublikacjaThe recycling of plastics is currently one of the most significant industrial challenges. Due to the enormous amounts of plastic wastes generated by various industry branches, it is essential to look for potential methods for their utilization. In the presented work, we investigated the recycling potential of wastes originated from the agricultural films recycling line. Their structure and properties were analyzed, and they were...
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Analysis of Corrugated Coaxial Line with the Use of Body of Revolution and Finite Element Method
PublikacjaA combination of the body-of-revolution and finite element methods is utilized to the analysis of coaxial lines with corrugated rod and wall. Both periodic and non-periodic structures can be investigated. As the structure is axially symmetrical the two dimensional scalar-vector finite element method can be used, which allows for the investigation of complex geometries and is computationally efficient. A generalized impedance matrix...
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3D POINT-CLOUD SPATIAL EXPANSION BY TOTAL LEAST-SQUARES LINE FITTING
PublikacjaPoint-cloud spatial expansion (PCSE) allows the creation of a new pointcloud form that presents an alternative geometry of an entire object in a single spatial view. Spatial expansion facilitates the analysis process and introduces an additional spatial parameter describing the point cloud. An important element of the PCSE method is determining the position of the axis of symmetry of a symmetrical object: the procedure for determining...
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Adaptive Identification of Underwater Acoustic Channel with a Mix of Static and Time-Varying Parameters
PublikacjaWe consider the problem of identification of communication channels with a mix of static and time-varying parameters. Such scenarios are typical, among others, in underwater acoustics. In this paper, we further develop adaptive algorithms built on the local basis function (LBF) principle resulting in excellent performance when identifying time-varying systems. The main drawback of an LBF algorithm is its high complexity. The subsequently...
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An investigation on residual stress and fatigue life assessment of T-shape welded joints
PublikacjaThis paper aims to quantitatively evaluate the residual stress and fatigue life of T-type welded joints with a multi-pass weld in different direction. The main research objectives of the experimental test were to test the residual stress by changing direction along with multiple wielding passes and determine the fatigue life of the welded joints. The result shows that compressive residual stress increases in the sample gradually...
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Porous Phantoms Mimicking Tissues – Investigation of Optical Parameter Stability Over Time
PublikacjaIn terms of optical parameters, optical phantoms can now replace live tissues and be used to validate optical measurement methods. Therefore, whether these parameters would be maintained after storage for 6 months was examined. The absorption and scattering coefficients were obtained from the measured transmittance and reflectance measurements taken 6 months apart and then compared. All of the measurements were conducted using...
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Neural modelling of dynamic systems with time delays based on an adjusted NEAT algorithm
PublikacjaA problem related to the development of an algorithm designed to find an architecture of artificial neural network used for black-box modelling of dynamic systems with time delays has been addressed in this paper. The proposed algorithm is based on a well-known NeuroEvolution of Augmenting Topologies (NEAT) algorithm. The NEAT algorithm has been adjusted by allowing additional connections within an artificial neural network and...
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Real-Time connection Between Immerse 3D Vizualization Laboratory and Kaskada Platform
PublikacjaMultimedia stream processing into two cooperative different systems (cluster platform and virtual lab) is considered. The considered selected information about the systems is presented and the idea of its communication when executing the distributed application is proposed. A general schema of the communication architecture is given. Tests of data transmission quality are considered and their results are presented.
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ADAPTIVE IDENTIFICATION OF TIME-VARYING IMPULSE RESPONSE OF UNDERWATER ACOUSTIC COMMUNICATION CHANNEL
PublikacjaThe transmission properties of underwater acoustic communication channel can change dynamically due to the movement of acoustic system transmitter and receiver or underwater objects reflecting transmitted signal. The time-varying impulse response measurement and estimation are necessary to match the physical layer of data transmission to instantaneous channel propagation conditions. Using the correlative measurement method, impulse...
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PCR and real-time PCR assays to detect fungi of Alternaria alternata species
PublikacjaFungi of the Alternaria genus are mostly associated with allergic diseases. However, with a growing number of immunocompromised patients, these fungi, with A. alternata being the most prevalent one, are increasingly recognized as etiological agents of infections (phaeohyphomycoses) in humans. Nowadays, identification of Alternaria spp. requires their pure culture and is solely based on morphological criteria. Clinically, Alternaria...
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Regularized Identification of Time-Varying FIR Systems Based on Generalized Cross-Validation
PublikacjaA new regularization method is proposed and applied to identification of time-varying finite impulse response systems. We show, that by a careful design of the regularization constraint, one can improve estimation results, especially in the presence of strong measurement noise. We also show that the the most appropriate regularization gain can be found by direct optimization of the generalized cross-validation criterion.
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Numerical Analysis of Recharge Rates and Contaminant Travel Time in Layered Unsaturated Soils
PublikacjaThis study focused on the estimation of groundwater recharge rates and travel time of conservative contaminants between ground surface and aquifer. Numerical simulations of transient water flow and solute transport were performed using the SWAP computer program for 10 layered soil profiles, composed of materials ranging from gravel to clay. In particular, sensitivity of the results to the thickness and position of weakly permeable...
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Real-time hybrid model of a wind turbine with doubly fed induction generator
PublikacjaIn recent years renewable sources have been dominating power system. The share of wind power in energy production increases year by year, which meets the need to protect the environment. Possibility of conducting, not only computer simulation, but also laboratory studies of wind turbine operation and impact on the power system and other power devices in laboratory conditions would be very useful. This article presents a method...
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Can we rely on the pulse transit time - pressure relationship - models comparison
PublikacjaAn unobtrusive, noninvasive and continuous pressure measurement is invaluable however, still being under research and development. There are many attempts proposing an appropriate relationship between pulse pressure velocity and pressure. Fifteen different formulas, both theoretical and experimental, describing relation between blood pressure and crosssectional area of the vessel were examined. Using these formulas the relation...
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Task Allocation and Scalability Evaluation for Real-Time Multimedia Processing in a Cluster Envirinment
PublikacjaAn allocation algorithm for stream processing tasks is proposed (Modified best Fit Descendent, MBFD). A comparison with another solution (BFD) is provided. Tests of the algorithms in an HPC environment are descrobed and the results are presented. A proper scalability metric is proposed and used for the evaluation of the allocation algorithm.
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THE PROBLEM OF THE CALCULATION OF THE FREQUENCY OF DIAGNOSTIC EXAMINATIONS BASED ON DEVICE’S PROPER OPERATION TIME
PublikacjaThe paper presents the proposal to apply the normal distribution to solve the problem of the frequency of diagnostic tests. Particular emphasis is placed on simplicity of the method. This method may be useful for the average user technical system. The method reduces the number of assumptions to a minimum. The results do not raise of serious doubts but they require verification of course.
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The influence of time of hearing aid use on auditory perception in various acoustic situations
PublikacjaThe assessment of sound perception in hearing aids, especially in the context of benefits that a prosthesis can bring, is a complex issue. The objective parameters of the hearing aids can easily be determined. These parameters, however, do not always have a direct and decisive influence on the subjective assessment of quality of the patient’s hearing while using a hearing aid. The paper presents the development of a method for...
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Impact of Shifting Time-Window Post-Processing on the Quality of Face Detection Algorithms
PublikacjaWe consider binary classification algorithms, which operate on single frames from video sequences. Such a class of algorithms is named OFA (One Frame Analyzed). Two such algorithms for facial detection are compared in terms of their susceptibility to the FSA (Frame Sequence Analysis) method. It introduces a shifting time-window improvement, which includes the temporal context of frames in a post-processing step that improves the...
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Improving methods for detecting people in video recordings using shifting time-windows
PublikacjaWe propose a novel method for improving algorithms which detect the presence of people in video sequences. Our focus is on algorithms for applications which require reporting and analyzing all scenes with detected people in long recordings. Therefore one of the target qualities of the classification result is its stability, understood as a low number of invalid scene boundaries. Many existing methods process images in the recording...
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Radar Signal Parameters Estimation Using Phase Accelerogram in the Time-Frequency Domain
PublikacjaRadar signal parameter estimation, in the context of the reconstruction of the received signal in a passive radar utilizing other radars as a source of illumination, is one of the fundamental steps in the signal processing chain in such a device. The task is also a crucial one in electronic reconnaissance systems, e.g. ELINT (Electronic Intelligence) systems. In order to obtain accurate results it is important to measure, estimate...
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Comparison of Surface Quality and Tool-Life of Glulam Window Elements after Planing
PublikacjaThe quality of the surface of wooden elements, that have been planed, has a crucial importance in the whole production process, since the obtained effects affect the quality of wooden surface after fi nishing (painting). The occurrence of defects is usually the reason for qualifying a workpiece as scrap or for requiring additional work. This paper presents the selected results of research of the effect of the cutting tool wear...