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Search results for: TIME-FREQUENCY ANALYSIS
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Frequency distribution of chemical oscillations in the closed Belousov Zhabotinsky reaction.
PublicationW publikacji przedstawiono wykorzystanie metody STFT (krótkoczasowej transformaty Fouriera) do analizy oscylacji chemicznych. Badano rejestry potencjałowe reakcji Biełousowa Żabotyńskiego. Wykazano niestacjonarność analizowanych przebiegów. Wykazano liniową zależność pomiędzy częstotliwością oscylacji a stężeniem jednego z komponentów reakcji (bromian potasu). Udowodniono przydatność analizy czasowo-częstotliwościowej do analizy...
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Application of residual current devices in electrical installations with frequency converters
PublicationW instalacjach elektrycznych, w których znajdują się przemienniki częstotliwości mogą pojawić się prądy zwarcia doziemnego o różnej częstotliwości lub stałe. Większość wyłączników różnicowoprądowych nie reaguje na tego typu prądy, co powoduje, że ochrona przeciwporażeniowa jest nieskuteczna. W obwodach z przemiennikami częstotliwości mogą pojawiać się przejściowe i ustalone prądy upływowe o znacznych wartościach. Prądy te znacząco...
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Landform Analysis
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An Industrial Survey on Business Analysis Problems and Solutions
PublicationThe paper focuses on the problems reported by business analysts which have a negative impact on their work and on the applicability of available business analysis (BA) techniques as solutions to such problems. A unified set of BA techniques was developed on the basis of 3 industrial standards associated with IIBA, REQB and IREB certification schemes. A group of 8 business analysts was surveyed to list problems they encounter in...
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Inline Waveguide Filter With Compact Frequency-Dependent Coupling Producing Two Additional Poles and Three Transmission Zeros
PublicationThis work reports a compact frequency-dependent coupling (FDC) structure introduced in a rectangular waveguide, which allows to generate two additional in-band transmission poles and three transmission zeros (TZs). This serves to increase the order/selectivity of the waveguide bandpass filter in a compact inline topology, thus without the need for any additional space/volume or cross coupling. The proposed FDC consists of a partial-height...
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Influence analysis of selected parameters on the ASON/GMPLS control plane performance
PublicationThe paper regards the problem of ASON/GMPLS performance. The authors present influence analysis of selected parameters on the ASON/GMPLS control plane performance represented in mean Connection Set-up Time E(CST) and mean Connection Release Time E(CRT). The selected parameters are: offered traffic, request intensity and proportion of requests class. The influence analysis is performed with simulation method by using OMNeT++ discrete-event...
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Fixed Pattern Noise Reduction and Linearity Improvement in Time-Mode CMOS Image Sensors
PublicationIn the paper, a digital clock stopping technique for gain and offset correction in time-mode analog-to-digital converters (ADCs) has been proposed. The technique is dedicated to imagers with massively parallel image acquisition working in the time mode where compensation of dark signal non-uniformity (DSNU) as well as photo-response non-uniformity (PRNU) is critical. Fixed pattern noise (FPN) reduction has been experimentally validated...
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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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Identification of the mechanical properties of the skin by electromechanical impedance analysis of resonant piezoelectric actuator
PublicationThis paper is devoted to the analysis and verification of developed piezoelectric sensor/actuator for measuring the mechanical properties of soft tissues, especially human skin. The key element of the measurement structure is an electromechanical system that uses both the reverse piezoelectric effect (vibration generation – stimulation of the tissues in the appropriate frequency range) and direct piezoelectric effect (system response...
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Thermogravimetric analysis (TGA) of the SrxTi0.30Fe0.70O3-d materials
Open Research DataThis dataset contains results of thermogravimetric analysis (TGA) fot SrxTi0.30Fe0.70O3-d materials (x=0.90, 0.95, 1.00 and 1.05). The TGA experiments were carried out using a microbalance (CI Precision MK5) in the temperature range between 900 °C and 200 °C. During the whole measurement procedure, air was fed to the furnace chamber at a flow rate of...
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Analysis of noise properties of the optocoupler device
PublicationIn the paper the localization of a source of Random Telegraph Signal noise (RTS noise) in optocoupler devices type CNY 17 were defined. The equivalent noise circuit in low frequency noise for these type optocouplers was proposed.
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Dead time effects compensation strategy by third harmonic injection for a five-phase inverter
PublicationThis paper proposes a method for compensation of dead-time effects for a fivephase inverter. In the proposed method an additional control subsystem was added to the field-oriented control (FOC) scheme in the coordinate system mapped to the third harmonic. The additional control loop operates in the fixed, orthogonal reference frame ( α - β coordinates) without the need for additional Park transformations. The purpose of this method...
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Investigations of the Methods of Time Delay Measurement of Stochastic Signals Using Cross-correlation with the Hilbert Transform
PublicationThe article presents the results of simulation studies of four methods of estimating time delay for random signals using cross-correlation with the Hilbert Transform. Selected models of mutually delayed stochastic signals were used in the simulations, corresponding to the signals obtained from scintillation detectors in radioisotope measurements of liquid-gas two-phase flow. Standard deviations of the values of the individual functions...
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RSS-Based DoA Estimation Using ESPAR Antenna for V2X Applications in 802.11p Frequency Band
PublicationIn this paper, we have proposed direction-of arrival (DoA) estimation of incoming signals for V2X applications in 802. 11p frequency band, based on recording of received signal strength (RSS) at electronically steerable parasitic array radiator (ESPAR) antenna's output port. The motivation of the work was to prove that ESPAR antenna used to increase connectivity and security in V2X communication can...
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Propagation analysis of the point-to-point radio links operating in the band
PublicationThe theoretical possibilities of utilizing the EHF-band frequencies for point-to-point short range communications have been discussed. The most important factors that affect propagation attenuation in this band have been briefly described, as well as relevant mathematical formulas that allow for numerical analysis of these phenomena. After that, a research have been carried out in which the authors have analyzed propagation losses...
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Mitigating Time-Constrained Stolen-Credentials Content Poisoning in an NDN Setting
PublicationNDN is a content-centric networking architecture using globally addressable information objects, created by publishers and cached by network nodes to be later accessed by subscribers. Content poisoning attacks consist in the substi-tution by an intruder publisher of bogus objects for genuine ones created by an honest publisher. With valid credentials stolen from an honest publisher, such attacks seem unstoppa-ble unless object...
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A Miniaturized and High Optically Transparent Frequency Selective Surface for RF Shielding using Double-Glazed Glass Windows for Green Building Applications
PublicationThis research presents a miniaturized and high optically transparent (OT) frequency selective surface (FSS) for achieving RF shielding through glass window panels. The proposed FSS consists of a single-layered copper pattern sandwiched between two ordinary glass substrates to suppress the dual bands of sub-6 fifth generation (5G). In particular, the design effectively shields n65-downlink (2.1 GHz) and a portion of n78-band (3.5...
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Real-time monitoring of the emission of volatile organic compounds from polylactide 3D printing filaments
PublicationEstablishing the emission profile of volatile organic compounds generated during fused deposition modeling 3D printing using polymer filaments is important in terms of both understanding the processes taking place during thermal degradation of thermoplastics, and assessing the user's exposure to potentially harmful volatiles. However, obtaining detailed, real-time qualitative and quantitative results poses a challenge. In this...
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Fast multi-criterial statistical analysis and design optimization of compact microwave couplers
Publication—A rapid statistical analysis and yield estimation of compact microwave couplers involving multiple performance parameters has been presented. The analysis is realized using a fast surrogate model representing appropriate characteristic points of the coupler response. Because of less nonlinear dependence of the characteristic points on the structure geometry (compared to the original response, i.e., S-parameters vs. frequency),...
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A Low-Profile Metal-backed Dipole Loaded with Closely Coupled Arc-shaped Open Stubs for On-metal Tag Design with Wide Frequency Tuning Capability
PublicationThis research has presented a single-layer metal-backed dipole antenna, which consists of a feedline loaded with two pairs of closely-coupled arc-shaped open stubs, for designing a metal-mountable tag that features tuning capability over a wide range of frequency. Here, the stubs can generate sufficient inductive reactance for bringing down the tag resonant frequency tunable in both the regulated UHF RFID passbands (North American...
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Hybrid technique for the analysis of circular waveguide junctions loaded with ferrite posts
PublicationThis study presents a hybrid technique for the analysis of circular waveguide junctions loaded with axially symmetrical ferrite posts of irregular shape. The method is based on a combination of the finite-difference frequency- domain technique with a mode-matching technique. The proposed approach is validated by comparing the presented results with numerical ones obtained from commercial software. The application of a cylindrical...
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Compensation Topologies in IPT Systems: Standards, Requirements, Classification, Analysis, Comparison and Application
PublicationWireless power transfer devices are becoming more relevant and widespread. Therefore, an article is devoted to a review, analysis and comparison of compensation topologies for an inductive power transfer. A new classification of topologies is developed. A lot of attention is paid to the problems of the physical fundamentals of compensation work, standards, safety, and five main topology requirements. It is determined, that topologies...
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Linux scheduler improvement for time demanding network applications, running on Communication Platform Systems
PublicationCommunication Platform Systems as ex. ATCA standard blades located in standardized chassis provides high level communication services between system peripherals. Each ATCA blade brings dedicated functionality to the system but can as well exist as separated host responsible for servicing set of task. According to platform philosophy these parts of system can be quite independent against another solutions provided by competitors....
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New and Fast Analytical Techniques in Food Quality Analysis
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Innovative Implantable Left Ventricular Assist Device—Performance under Various Resistances and Operating Frequency Conditions
PublicationThis paper presents the operation of an innovative left ventricular assist device under various resistances and operating frequencies. The operating principle of the device is based on pulsatile blood flow, which is forced by a suction–discharge device pumping helium into a set of intra-cardiac balloons. In this way, the ejection fraction of the left ventricle is increased, and the mitral valve is additionally occluded. What is...
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Systemic analysis of a manufacturing process based on a small scale bakery
PublicationThe main aim of the article is to present two new innovative concepts of reliability of a functioning manufacturing system in the process of making bread in small-scale bakeries. Reliability is understood as one of the representations of an operator acting on specifc streams in time to - t. One of these represents the global reliability of a system as a function of parallel action of all the streams of the system in time to to...
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CMOS implementation of an analogue median filter for image processing in real time
PublicationAn analogue median filter, realised in a 0.35 μm CMOS technology, is presented in this paper. The key advantages of the filter are: high speed of image processing (50 frames per second), low-power operation (below 1.25 mW under 3.3 V supply) and relatively high accuracy of signal processing. The presented filter is a part of an integrated circuit for image processing (a vision chip), containing: a photo-sensor matrix, a set of...
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Dynamics analysis of footbridge mode shapes the s8 expressway on the basis of the results of in situ tests
PublicationNon-destructive diagnostics for structure may use dynamic measurements realized during vibrations of a facility induced by dynamic environmental impact, enforced by the use of inductors or impulse impact. Dynamic tests and the analysis were undertaken for a footbridge situated over the expressway S8. The studies in situ allowed for dynamic characteristics to be determined: frequency, shape modes and damping for respective frequency...
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Geometrically nonlinear analysis of shells - Benchmark problems for Autocad Robot Analysis Professional
PublicationThe aim of this work is to verify the suitability of commercial engineering software for geometrically nonlinear analysis of shells. This paper deals with the static, geometrically nonlinear analysis of shells made of an isotropic material. The Finite Element Method (FEM) is chosen to solve the problem. The results of the commercial software Autocad Robot Structural Analysis Professional (ARSAP) are compared with the litera-ture...
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Reduced-order models in the finite element analysis
PublicationA novel technique of incorporating macromodels into finite element electromagnetic analysis of waveguide components is presented. Macromodels are generated by using a model order reduction algorithm (ENOR), which results in significant decrease of the number of variables, that describe the computational region. Proposed technique allows for using a few independent macromodels as well as to duplicating one macromodel in many subregions...
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PLE in the analysis of plant compounds
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PLE in the analysis of plant compounds
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Fast Algorithms for Identification of Time-Varying Systems with Both Smooth and Discontinuous Parameter Changes
PublicationThe problem of noncausal identification of a time-varying linear system subject to both smooth and occasional jump-type changes is considered and solved using the preestimation technique combined with the basis function approach to modeling the variability of system parameters. The proposed estimation algorithms yield very good parameter tracking results and are computationally attractive.
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NON-LINE ANALYSIS OF STIFFNESS IN COMPRESSION CONDITIONS
PublicationThe analyzes were aimed at demonstrating the influence of parameters describing the deformation of the structure on the uncertainty of critical force, and the impact of technological imperfections on stress uncertainty in compression conditions. In a linear buckling analysis, the problem is considered only for the initial, permanent state of the stiffness matrix. In the case of demonstrating the influence of initial deformations...
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Analytical Expression for the Time-Domain Discrete Green's Function of a Plane Wave Propagating in the 2-D FDTD Grid
PublicationIn this letter, a new closed-form expression for the time-domain discrete Green's function (DGF) of a plane wave propagating in the 2-D finite-difference time-domain (FDTD) grid is derived. For the sake of its verification, the time-domain implementation of the analytic field propagator (AFP) technique was developed for the plane wave injection in 2-D total-field/scattered-field (TFSF) FDTD simulations. Such an implementation of...
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Analytical Expression for the Time-Domain Green's Function of a Discrete Plane Wave Propagating in the 3-D FDTD Grid
PublicationIn this paper, a closed-form expression for the time-domain dyadic Green’s function of a discrete plane wave (DPW) propagating in a 3-D finite-difference time-domain (FDTD) grid is derived. In order to verify our findings, the time-domain implementation of the DPW-injection technique is developed with the use of the derived expression for 3-D total-field/scattered-field (TFSF) FDTD simulations. This implementation requires computations...
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Inline Microstrip Bandpass Filter With Two Transmission Zeros and Increased Order Using Spurious Resonance of Frequency-Dependent Inverter
PublicationA design method for a class of fourth-order inline microstrip bandpass filter with two transmission zeros and 20% fractional bandwidth is presented. The filter consists of two quarter-wavelength transmission-line resonators coupled by a frequency-dependent inverter. The inverter is composed of two open-ended stubs that are connected by an interdigital capacitor and introduces two poles and two transmission zeros in the filter response....
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Experimental and numerical analysis of the modified TB32 crash tests of the cable barrier system
PublicationRoad restraint systems, including safety barriers, are one of the means used to improve road safety. Currently, they can be allowed to general use after passing the specific crash tests. However, it is always important and desirable to evaluate their performance under various realistic conditions, which can happen on the roads. In this study, the behaviour of the cable barrier system in impact conditions different than assumed...
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Performance of DS-CDMA Radionavigation Receiver with Subsample Time Measurement Resolution in Various Environments
PublicationThis paper presents results of investigation of position estimation performance in TDOA radionavigation system with receiver containing code tracking loop with subsample time measurement resolution. Position estimation accuracy was evaluated using real signals from CDMA base stations, recorded during measurement campaigns in various environments: on sea, flat terrain and hilly terrain.
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Applications of the discrete green's function in the finite-difference time-domain method
PublicationIn this paper, applications of the discrete Green's function (DGF) in the three-dimensional (3-D) finite-difference time-domain (FDTD) method are presented. The FDTD method on disjoint domains was developed employing DGF to couple the subdomains as well as to compute the electromagnetic field outside these subdomains. Hence, source and scatterer are simulated in separate subdomains and updating of vacuum cells, being of little...
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Derivation of motor mean phase currents in PMSM drives operating with low switching-to-fundamental frequency ratio
PublicationPulse width modulation (PWM) of inverter output voltage causes the waveforms of motor phase cur-rents to consist of distinctive ripples. In order to provide suitable feedback for the motor current con-trollers, the mean value must be extracted from the currents’ waveforms in every PWM cycle. A com-mon solution to derive the mean phase currents is to sample their value at the midpoint of a symmetrical PWM cycle. Using an assumption...
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Real-time monitoring of volatiles and particles emitted from thermoplastic filaments during 3D printing
PublicationThe proliferation of consumer-grade three-dimensional (3D) printers using fused deposition, also known as fused filament fabrication, has given rise to concerns over the exposure of users to potentially harmful substances. Thermoplastic filaments made of different polymers are extruded through a heated printer nozzle and deposited layer by layer on a build platform to form the printed object. This process leads to the emission...
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The surface of the sensor used in the analysis of odorous substances
Open Research DataHuman industrial activity usually leads to smaller or larger interference with the ecosystem, contributing to changes affecting the quality of life. An example may be the emission of gaseous substances, not necessarily toxic, but due to their intense smell, they can cause discomfort to people exposed to their inhalation. The problem is so important...
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International Journal of Embedded and Real-Time Communication Systems
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Exhaled breath analysis by resistive gas sensors
PublicationBreath analysis has attracted human beings for centuries. It was one of the simplest methods to detect various diseases by using human smell sense only. Advances in technology enable to use more reliable and standardized methods, based on different gas sensing systems. Breath analysis requires the detection of volatile organic compounds (VOCs) of the concentrations below individual ppm (parts per million). Therefore, advanced detection...
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Automatic Cleaning of Time Series Data in Rural Internet of Things Ecosystems That Use Nomadic Gateways
PublicationA serious limitation to the deployment of IoT solutions in rural areas may be the lack of available telecommunications infrastructure enabling the continuous collection of measurement data. A nomadic computing system, using a UAV carrying an on-board gateway, can handle this; it leads, however, to a number of technical challenges. One is the intermittent collection of data from ground sensors governed by weather conditions for...
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Phylogenetic trees of genus Oncidium Sw. based on analysis of DNA sequences
Open Research DataGenus Oncidium Sw. is widely regarded as a polyphiletic, and the taxonomic boundaries between him and such genera as Odontoglossum Kunth. or Miltonia Lindley remain blurred. The goal of the study was to determine the phylogenetic relationships within the genus Oncidium s.lato based on the DNA sequences analysis. The correlation between molecular data...
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Radar time budget optimization subject to angle accuracy constraint via cognitive approach
PublicationThe problem of minimizing dwell time in multifunction phased array radar is considered. Target of interest is assumed to fluctuate according to a generalization of Swerling family and the parameters of fluctuation model are assumed to be known. The a'priori position of the target is uncertain. Optimization, whose variables include pulse count and array transmit beampattern, is carried out subject to achieving a desired accuracy...
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Modeling and Simulation for Exploring Power/Time Trade-off of Parallel Deep Neural Network Training
PublicationIn the paper we tackle bi-objective execution time and power consumption optimization problem concerning execution of parallel applications. We propose using a discrete-event simulation environment for exploring this power/time trade-off in the form of a Pareto front. The solution is verified by a case study based on a real deep neural network training application for automatic speech recognition. A simulation lasting over 2 hours...
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Polski PR-owiec w świecie ponowoczesnym – wyniki badań i ich analiza. Poza dobrem i złem
PublicationW artykule analizuję wyniki badania Profesjonalizm public relations w Polsce, przeprowadzonego na potrzeby budowanego dokumentu Standardy profesjonalnego public relations – prezentowanego w tej pracy. Stawiam również pytanie o przyczynę częstych odpowiedzi respondentów „czasami” czy „nie mam zdania” i wykazuję niespójność systemów wartości respondentów zestawiając ich odpowiedzi na poszczególne pytania. Stawiam tezę, że niespójności...