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Search results for: TIME–FREQUENCY REASSIGNMENT
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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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On the lower smoothing bound 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 in 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. Assuming that the infinite observation history is available, the paper...
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Time sprawl: czy zagraża nam urbanizacja nocy?
PublicationMechanizmy działające w mieście zachodzą zazwyczaj z niezwykłą nieuchronnością, a przemiany cywilizacyjne stają się faktem niezależnie od woli mieszkańców. W ciągu ostatnich lat w polskich miastach poszczególne usługi coraz bardziej wydłużają czas funkcjonowania w ciągu doby starając się nadążyć za zmieniającymi się przyzwyczajeniami klientów. Wydaje się, że zjawisko rozciągania czasu aktywności miasta może być równie szkodliwe...
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Time-domain prosodic modifications for text-to-speech synthesizer
PublicationAn application of prosodic speech processing algorithms to Text-To-Speech synthesis is presented. Prosodic modifications that improve the naturalness of the synthesized signal are discussed. The applied method is based on the TD-PSOLA algorithm. The developed Text-To-Speech Synthesizer is used in applications employing multimodal computer interfaces.
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Tackling age-related disease: time for a step forward
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Stability by linear approximation for time scale dynamical systems
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Uniform solvability for families of linear systems on time scales
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CMOS Low-Dropout Regulator With Improved Time Response
PublicationPrzedstawiono nową konfigurację regulatora o obniżonym spadku napięcia, w którym wykorzystano stopień wyjściowy z równoległym sprzężeniem napięciowym. Dzięki obniżonej rezystancji wyjściowej stopnia, uzyskano poprawę odpowiedzi impulsowej regulatora na szybką zmianę prądu wyjściowego.
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Neural network breast cancer relapse time prognosis
PublicationPrzedstawiono architekturę i wyniki testowania sztucznej sieci neuronowej w prognozowaniu czasu nawrotu choroby u kobiet chorych na raka piersi. Sieć neuronowa uczona była na danych zgromadzonych przez 20 lat. Dane opisują grupę 439 pacjentów za pomocą 40 parametrów. Spośród tych parametrów wybrano 6 najistotniejszych: liczbę przerzutowych węzłów chłonnych, wielkość guza, wiek, skalę według Blooma oraz stan receptorów estrogenowych...
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A reliable synthesis of discrete-time H-inf control. Part I: basic theorems and J-lossless conjugators
PublicationThe paper gives a basis for solving many problems of numerically reliable synthesis of sub-optimal discrete-time control in H-inf. The approach is based on J-lossless factorisation of the delta-domain chain-scattering description of continuous-time plants being controlled. Relevant properties of poles and zeroes of chain-scattering models are given. Necessary and sufficient conditions for the existence of stabilising J-lossless...
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Long-distance quantum communication over noisy networks without long-time quantum memory
PublicationThe problem of sharing entanglement over large distances is crucial for implementations of quantum cryptography. A possible scheme for long-distance entanglement sharing and quantum communication exploits networks whose nodes share Einstein-Podolsky-Rosen (EPR) pairs. In Perseguers et al. [Phys. Rev. A 78, 062324 (2008)] the authors put forward an important isomorphism between storing quantum information in a dimension D and transmission...
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Crack monitoring in concrete beams under bending using ultrasonic waves and coda wave interferometry: the effect of excitation frequency on coda
PublicationConcrete is one of the most widely used construction materials in the world. In recent years, various non-destructive testing (NDT) and structural health monitoring (SHM) techniques have been investigated to improve the safety and control of the current condition of concrete structures. This study focuses on micro-crack monitoring in concrete beams. The experimental analysis was carried out on concrete elements subjected to three-point...
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Effective Permeability of Multi Air Gap Ferrite Core 3-Phase Medium Frequency Transformer in Isolated DC-DC Converters
PublicationThe magnetizing inductance of the medium frequency transformer (MFT) impacts the performance of the isolated dc-dc power converters. The ferrite material is considered for high power transformers but it requires an assembly of type “I” cores resulting in a multi air gap structure of the magnetic core. The authors claim that the multiple air gaps are randomly distributed and that the average air gap length is unpredictable at the...
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Effect of Time Varying Measurement Conditions on Antenna Pattern in Near Field Measurement and Its Correction Procedure
PublicationAuthors present the procedure of taking into account the changes of electrical parameters of setup due to the time drift of temperature during the procedure of near field measurement. It is proposed to make additional measurements in determined positions of probe are next used the results to introduce corrections terms in measured data. Such approach was verified practically in experimental near field measurement system.
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Anharmonic Infrared Spectroscopy through the Fourier Transform of Time Correlation Function Formalism in ONETEP
PublicationDensity functional theory molecular dynamics (DFT-MD) provides an efficient framework for accurately computing several types of spectra. The major benefit of DFTMD approaches lies in the ability to naturally take into account the effects of temperature and anharmonicity, without having to introduce any ad hoc or a posteriori corrections. Consequently, computational spectroscopy based on DFT-MD approaches plays a pivotal role in...
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Influence of the analyzing window on electrode impedance measurement by the continuous frequency scanning method
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Experimental Investigation of high frequency 3L-NPC qZS inverter for photovoltaic application
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DoA Estimation Using Reconfigurable Antennas in Millimiter-Wave Frequency 5G Systems
PublicationTo achieve low latency and high throughputs, future 5G systems will have to utilize complex antenna systems able to provide beamforming and direction-of-arrival (DoA) estimation capabilities. Most of the concepts available in the literature rely on analog or digital beamforming, which is well developed and can be used both at a base station and in a user terminal. However, in applications, in which...
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Ladder-Based Synthesis and Design of Low-Frequency Buffer-Based CMOS Filters
PublicationBuffer-based CMOS filters are maximally simplified circuits containing as few transistors as possible. Their applications, among others, include nano to micro watt biomedical sensors that process physiological signals of frequencies from 0.01 Hz to about 3 kHz. The order of a buffer-based filter is not greater than two. Hence, to obtain higher-order filters, a cascade of second-order filters is constructed. In this paper, a more...
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A new class of eigenfunction expansion methods for fast frequency-domain analysis of waveguides
PublicationZaprezentowano nową technikę szybkiego obliczania charakterystyk dyspersyjnych falowodów z niejednorodnym wypełnieniem. Metoda ta oblicza przybliżone wartości stałej propagacji dla wymaganej częstotliwości, bazując na bardziej dokładnych wyliczeniach rozkładu pola i stałej propagacji dla kilku wybranych punktów częstotliwości.
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The influence of frequency controlled ac drives on vibration and audible noise level on ships
PublicationOkreślono korelacje między zakłóceniami elektrycznymi a wibracjami i hałasem w okrętowych układach napędowych z przemiennikami częstotliwości. Wskazano na destrukcyjny wpływ tych czynników na jakość życia załóg pływających.
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Conditions for measurement, analog-to-digital conversion and frequency analysis of irregularities of profile surface
PublicationPrzedstawiono uwarunkowania pomiaru, przetwarzania analogowo-cyfrowego i analizy częstotliwościowej nierówności powierzchni toczonych dla celów rozpoznawania ich głównych składowych. Przedstawiono ograniczenia w pomiarze igłą, która odwzorowuje nierówności poprzeczne. Podano zależności parametrów pomiaru cyfrowego nierówności warunkujące zakresy ich rozpatrywania. Dla wartości przedziału próbkowania, dla którego nie jest spełnione...
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<title>Spectrum analysis of measuring signals in sensor circuits with frequency outputs</title>
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Dynamic Analysis of an Enhanced Multi-Frequency Inertial Exciter for Industrial Vibrating Machines
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Cylindrical surface irregularities presented by frequency spectra of relative tool displacement to the workpiece
PublicationW pracy przedstawiono częstotliwościowe składowe nierówności powierzchni toczonych. Ponieważ nierówności mają charakter szerokopasmowy, trudny do wartościowania parametrami normatywnymi, zastosowano ich analizę amplitudowo-częstotliwościową, opartą na szybkiej transformacie Fouriera. Zaproponowano oryginalny układ pomiaru sygnału przemieszczeń narzędzia względem przedmiotu dla charakteryzowania nierówności wzdłużnych. Dla generowania...
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Cylindrical surface irregularities presented by frequency spectra of relative tool displacement to the workpiece
PublicationW pracy przedstawiono częstotliwościowe składowe nierówności powierzchni toczonych. Ponieważ nierówności mają charakter szerokopasmowy, trudny do wartościowania parametrami normatywnymi, zastosowano ich analizę amplitudowo-częstotliwościową, opartą na szybkiej transformacie Fouriera. Zaproponowano oryginalny układ pomiaru sygnału przemieszczeń narzędzia względem przedmiotu dla charakteryzowania nierówności wzdłużnych. Dla generowania...
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Experimental investigations of interturn faults in transformer winding using frequency response analysis
PublicationW referacie przedstawiono wyniki badań eksperymentalnych specjalnego Transformatora Trakcyjnego o Zredukowanej Skali (TTZS) z wykorzystaniem metody analizy odpowiedzi w dziedzinie częstotliwości. Pokazano wybrane wyniki analiza FRA nieuszkodzonych symetrycznych uzwojeń strony wtórnej. Zmierzono widmo amplitudowe w przypadku zwarć zwojowych pojedynczych zwojów niektórych cewek. Wykazano, że miejsce wystąpienia zwarcia zwojowego...
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Detection of low- and high-frequency rhythms in the variability of skin sympathetic nerve activity
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Low Frequency Noise Measurement of Reverse Polarized Silicon Carbide Schottky Diodes
PublicationW artykule przedstawiono wyniki pomiaró szumów cz. wstecznie spolaryzowanych diod Schottky'ego.
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Low frequency of itraconazole resistance found among avian Aspergillus fumigatus isolates
PublicationAspergillus fumigatus is the most frequent etiological factor of invasive aspergillosis in human as well as animals, including birds. Aspergillosis caused by drug-resistant strains poses a significant therapeutic issue, especially if resistance pattern includes insensitivity to triazoles, i.e. drugs recommended for the primary therapy purposes. Majority of resistant isolates hold the TR34/L98H...
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The measurement of input power of power supply in network disturbed by low frequency distortions
PublicationIn the paper authors present results of observation of input power changes versus harmonics amplitude in supply voltage of low-power power supply device. In the study, the electrical measurements supported with thermal imaging were used. The input circuit elements of studied device responsible for input power increase are pointed
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Excitation of Non-Wave Modes by Sound of Arbitrary Frequency in a Chemically Reacting Gas
PublicationThe nonlinear phenomena in the field of high intensity sound propagating in a gas with a chemical reaction, are considered. A chemical reaction of A → B type is followed by dispersion and attenuation of sound which may be atypical during irreversible thermodynamic processes under some conditions. The first and second order derivatives of heat produced in the chemical reaction evaluated at the equilibrium temperature, density and...
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Compatible DC and small-signal MOSFET models for radio and microwave frequency simulation
PublicationZaprezentowano nowy model stałoprądowy tranzystora MOS i kompatybilny z nim uogólniony nie-quasi-statyczny model małosygnałowy. Model stałoprądowy został eksperymentalnie zweryfikowany dla tranzystorów MOS o długości kanału od 75 nm do kilkunastu mikrometrów, a model małosygnałowy od zera herców do 30 GHz.
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Real-Time Facial Features Detection from Low Resolution Thermal Images with Deep Classification Models
PublicationDeep networks have already shown a spectacular success for object classification and detection for various applications from everyday use cases to advanced medical problems. The main advantage of the classification models over the detection models is less time and effort needed for dataset preparation, because classification networks do not require bounding box annotations, but labels at the image level only. Yet, after passing...
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Gender as a moderator between Present-Hedonistic time perspective and depressive symptoms or stress during COVID-19 lock-down
PublicationAlthough numerous studies have addressed the impact of the COVID-19 lock-downs on psychological distress, scarce data is available relating to the role of Present-Hedonistic (PH) time perspective and gender differences in the development of depressive symptoms and stress during the period of strict social distancing. We hypothesized that gender would moderate the relationship between PH and depressiveness or stress levels, such...
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A Time Delay Controller Included Terminal Sliding Mode and Fuzzy Gain Tuning for Underwater Vehicle-Manipulator Systems
PublicationAn improved Time Delay Control (TDC) method for an Underwater Vehicle-Manipulator System (UVMS) is proposed. The proposed controller consists of three terms: a time-delay-estimation term that cancels nonlinearities of the UVMS dynamics, a Terminal Sliding Mode (TSM) term that provides a fast response and a PID term that reduces the tracking error. In addition the proposed controller uses fuzzy rules to adaptively tune the gains...
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Excited state properties of a series of molecular photocatalysts investigated by time dependent density functional theory.
PublicationTime dependent density functional theory calculations are applied on a series of molecular photocatalysts of the type [(tbbpy)2M1(tpphz)M2X2]2+ (M1 = Ru, Os; M2 = Pd, Pt; X = Cl, I) in order to provide information concerning the photochemistry occurring upon excitation of the compounds in the visible region. To this aim, the energies, oscillator strengths and orbital characters of the singlet and triplet excited states are investigated....
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Estimation of Conservative Contaminant Travel Time through Vadose Zone Based on Transient and Steady Flow Approaches
PublicationEstimation of contaminant travel time through the vadose zone is needed for assessing groundwater vulnerability to pollution, planning monitoring and remediation activities or predicting the effect of land use change or climate change on groundwater quality. The travel time can be obtained from numerical simulations of transient flow and transport in the unsaturated soil profile, which typically require a large amount of data and...
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PCR and real-time PCR approaches to the identification of Arthroderma otae species Microsporum canis and Microsporum audouinii/Microsporum ferrugineum
PublicationObjectives The identification of species in the Arthroderma otae complex is essential to determine the origin of infection and to eliminate the risk of transmission. Microsporum canis is a zoophilic species, whereas Microsporum audouinii and Microsporum ferrugineum are anthropophilic species. In this paper, we propose alternative methods that permit species-specific identification of both anthropophilic and zoophilic members of...
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Research of chitosan coatings deposited by electrophoretic deposition method at various voltage and time parameters
PublicationThe aim of this research is to estimate the electrophoretic deposition main parameters, such as voltage and time duration, that will provide optimal characteristics of the surface layer. Chitosan coatings were synthesized on biomedical Ti13Zr13Nb alloys at 20 V and 30 V and with deposit times of 2min, 5 min, 10 min, and 15 min. Evaluation of the coating was performed by using Scanning Electron Microscope (SEM), Energy-Dispersive...
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Study of Nanohydroxyapatite Coatings Prepared by the Electrophoretic Deposition Method at Various Voltage and Time Parameters
PublicationThe aim of the work is to compare the properties of nanohydroxyapatite coatings obtained using the electrophoretic deposition method (EDP) at 10 V, 20 V, and 30 V, and with deposit times of 2 and 5 min. The primary sedimentation was used to minimize the risk of the formation of particle agglomerates on the sample surface. Evaluation of the coating was performed by using a Scanning Electron Microscope (SEM), Energy-Dispersive Spectroscopy...
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The dying medium temperature impact on the final moisture content of pine wood at constant drying time
PublicationThe results of final moisture content of pine wood (Pinus sylvestris L.) after drying process are presented. The wood in the experiments was taken from the northern part of Pomeranian region in Poland. The drying process was performed in the experimental chamber equipped with the micro-jet heat exchanger. The air at temperatures of 40°C, 60°C, 80°C, 100°C and 120°C with relative humidity about 60% and atmospheric pressure was the...
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Parametric method applicable in assessing breakout force and time for lifting slender bodies from seabed
PublicationThe article presents a parametric method applicable in assessing the suction force of a slender body to the seabed, and prognosing the body extrication time. Along with the body weight in water, the information on the suction force is essential for assessing the force needed to lift the object from the seabed. Based on the Foda theory and the resulting integral equation, which relates the maximum suction force with basic parameters...
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The Impact of Long-Time Chemical Bonds in Mineral-Cement-Emulsion Mixtures on Stiffness Modulus
PublicationDeep cold in-place recycling is the most popular method of reuse of existing old and deteriorated asphalt layers of road pavements. In Poland, in most cases, the Mineral-Cement-Emulsion mixture technology is used, but there are also applications combining foamed bitumen and cement. Mineral-Cement-Emulsion mixtures contain two different binding agents – cement as well as asphalt from the asphalt emulsion. Asphalt creates asphalt...
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Recent Advances in Accelerated Multi-Objective Design of High-Frequency Structures using Knowledge-Based Constrained Modeling Approach
PublicationDesign automation, including reliable optimization of engineering systems, is of paramount importance for both academia and industry. This includes the design of high-frequency structures (antennas, microwave circuits, integrated photonic components), where the appropriate adjustment of geometry and material parameters is crucial to meet stringent performance requirements dictated by practical applications. Realistic design has...
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Cost-Efficient Surrogate Modeling of High-Frequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
PublicationSurrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)-driven design of high-frequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problem-specific knowledge....
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System do diagnostyki dermatofitowych zakażeń powierzchniowych oparty na technice Real-Time PCR
PublicationDermatofity należą do blisko spokrewnionej grupy grzybów, które wykazują wysokie powinowactwo do skeratynizowanych tkanek. Cecha ta czyni je odpowiedzialnymi za powierzchniowe grzybice skóry, paznokci oraz włosów. Szacuje się, iż nawet do 20% ludzi na całym świecie dotkniętych jest infekcjami powodowanymi przez dermatofity. Ich leczenie wymaga długotrwałego zastosowania leków przeciwgrzybiczych. W celu dobrania odpowiedniego leczenia...
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Low-cost and reliable geometry scaling of compact microstrip couplers with respect to operating frequency, power split ratio, and dielectric substrate parameters
PublicationA technique for rapid re-design of miniaturised microstrip couplers with respect to operating conditions as well as material parameters of the dielectric substrate is proposed. The dimension scaling process is based on a set of pre-optimised reference designs, obtained for an equivalent circuit model of the coupler at hand. The reference designs are utilised to construct an inverse surrogate model which – upon suitable correction...
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Long‐time scale simulations of virus‐like particles from three human‐norovirus strains
PublicationThe dynamics of the virus like particles (VLPs) corresponding to the GII.4 Houston, GII.2 SMV, and GI.1 Norwalk strains of human noroviruses (HuNoV) that cause gastroenteritis was investigated by means of long-time (about 30 μs in the laboratory timescale) molecular dynamics simulations with the coarse-grained UNRES force field. The main motion of VLP units turned out to be the bending at the junction between the P1 subdomain (that...
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Using On-line Measurement by Electronic Nose and Computer Simulations for Real-time Control at WWTP
PublicationContinuous investigation of wastewater quality can be carried out by a device called an e-nose. One important feature of the proposed real-time control system for WWTP is that using on-line measurements by e-nose together (Figure 1) with technological sets picked on this basis by means of computer models, it is possible to change treatment process parameters, depending on the current quality of wastewater. It can be used for the...