Filtry
wszystkich: 2159
wybranych: 1835
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: NON-LINEAR CONTINUOUS-TIME MODELS
-
Application of wavelet transform in analysis of guided wave propagation signals for damage detection in a steel plate
PublikacjaThe paper presents results of experimental investigations on damage detection using guided wave propagation technique. The tested specimen was a steel plate with a defect in the form of a rectangular notch. Lamb waves were excited by a PZT actuator and sensed by a laser vibrometer. Since reflections from damage in registered signals are often masked by measurement noise, for identification of time of reflections from damage, continuous...
-
Comparison of tuning procedures based on evolutionary algorithm for multi-region fuzzy-logic PID controller for non-linear plant
PublikacjaThe paper presents a comparison of tuning procedures for a multi-region fuzzy-logic controller used for nonlinear process control. This controller is composed of local PID controllers and fuzzy-logic mechanism that aggregates local control signals. Three off-line tuning procedures are presented. The first one focuses on separate tuning of local PID controllers gains in the case when the parameters of membership functions of fuzzy-logic...
-
A non-uniform real-time speech time-scale stretching method
PublikacjaAn algorithm for non-uniform real-time speech stretching is presented. It provides a combination of typical SOLA algorithm (Synchronous Overlap and Add ) with the vowels, consonants and silence detectors. Based on the information about the content and the estimated value of the rate of speech (ROS), the algorithm adapts the scaling factor value. The ability of real-time speech stretching and the resultant quality of voice were...
-
Quality assessment of ZnO-based varistors by 1/f noise
PublikacjaNoise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented....
-
On the non-linear dynamics of torus-shaped and cylindrical shell structures
PublikacjaIn this study, the non-linear dynamic analysis of torus-shaped and cylindrical shell-like structures has been studied. The applied material is assumed as the functionally graded material (FGM). The structures are considered to be used for important machines such as wind turbines. The effects of some environmental factors on the analysis like temperature and humidity have been considered. The strain field has been calculated in...
-
Impedance monitoring of corrosion degradation of plasma electrolytic oxidation coatings (PEO) on magnesium alloy
PublikacjaImpedance technique based on continuous multisinusoidal current perturbation was used to explain degradation process of plasma electrolytic oxidation coatings (PEO) on magnesium alloy. An obtained impedance spectrum was fitted by electrical equivalent circuit to describe properties of conversion layer on magnesium alloy. Additionally, galvanostatic mode maintained during experiment, with DC current equal to zero, allowed to achieve...
-
Comparative Study of Integer and Non-Integer Order Models of Synchronous Generator
PublikacjaThis article presents a comparison between integer and non-integer order modelling of a synchronous generator, in the frequency domain as well as in the time domain. The classical integer order model was compared to one containing half -order systems. The half-order systems are represented in a Park d-q axis equivalent circuit as impedances modelled by half-order transmittances. Using a direct method based on the approximation...
-
Linear and Non-linear Decomposition of Index Generation Functions
Publikacja -
The optimization of enzyme immobilization at Au-Ti nanotextured platform and its impact onto the response towards glucose in neutral media
PublikacjaThe market of non-invasive glucose sensors is drastically growing due to increasing number of people suffering from diabetes. Therefore, there is a significant need for any improvement in the field of biosensors that can be used for monitoring glucose level in human body. In recent years the emphasis is put onto the modification of electrode material with enzymes possessing recognition centre specific towards particular molecules....
-
On Nature-Inspired Design Optimization of Antenna Structures Using Variable-Resolution EM Models
PublikacjaNumerical optimization has been ubiquitous in antenna design for over a decade or so. It is indispensable in handling of multiple geometry/material parameters, performance goals, and constraints. It is also challenging as it incurs significant CPU expenses, especially when the underlying computational model involves full-wave electromagnetic (EM) analysis. In most practical cases, the latter is imperative to ensure evaluation reliability....
-
Non-Linear Analysis of Structures Utilizing Load-Discretization of Stiffness Matrix Method with Coordinate Update
PublikacjaThis paper proposes a stiffness method based structural analysis algorithm for geometrically non-linear structures. In this study, the applied load on the joints has been discretized to a sequence of a few loadings applied. Each loading step produces incremental external nodal displacements, which are added to the corresponding coordinates to get a new geometrical shape of the structure. This process is iteratively repeated until...
-
Weak forms of shadowing in topological dynamics
PublikacjaWe consider continuous maps of compact metric spaces. It is proved that every pseudotrajectory with sufficiently small errors contains a subsequence of positive density that is point-wise close to a subsequence of an exact trajectory with the same indices. Also, we study homeomor- phisms such that any pseudotrajectory can be shadowed by a finite number of exact orbits. In terms of numerical methods this property (we call it multishadowing)...
-
Monitoring the fracture process of concrete during splitting using integrated ultrasonic coda wave interferometry, digital image correlation and X-ray micro-computed tomography
PublikacjaThe paper deals with the continuous-time monitoring of mechanical degradation in concrete cubes under splitting. A series of experiments performed with integrated coda wave interferometry (CWI) and digital image correlation (DIC), supported with X-ray micro-computed tomography (micro-CT) is reported. DIC and micro-CT techniques were used to characterize the fracture process in detail. CWI method was proved to be effective in the...
-
Automotive Validation Functions for On-line Test Evaluation of Hybrid Real-time Systems
PublikacjaThe aim of this paper is to present the means of black-box on-line test evaluation for hybrid real-time systems. The described procedures can be used for the model-based testing process so as to improve its effectiveness. In particular, intelligent automotive validation functions are considered, which are divided into different types depending on the nature of the evaluated issue. All provided definitions are specified on the meta-model...
-
A Method of Real-Time Non-uniform Speech Stretching
PublikacjaDeveloped method of real-time non-uniform speech stretching is presented.The proposed solution is based on the well-known SOLA algorithm(Synchronous Overlap and Add). Non-uniform time-scale modification isachieved by the adjustment of time scaling factor values in accordance with thesignal content. Dependently on the speech unit (vowels/consonants), instantaneousrate of speech (ROS), and speech signal presence, values of the scalingfactor...
-
Application Isssues of the Semi-Markov Reliability Model
PublikacjaPredicting the reliability of marine internal combustion engines, for instance, is of particular importance, as it makes it possible to predict their future reliability states based on the information on the past states. Correct reliability prediction is a complex process which consists in processing empirical results obtained from operating practice, complemented by analytical considerations. The process of technical state changes...
-
Marking the Allophones Boundaries Based on the DTW Algorithm
PublikacjaThe paper presents an approach to marking the boundaries of allophones in the speech signal based on the Dynamic Time Warping (DTW) algorithm. Setting and marking of allophones boundaries in continuous speech is a difficult issue due to the mutual influence of adjacent phonemes on each other. It is this neighborhood on the one hand that creates variants of phonemes that is allophones, and on the other hand it affects that the border...
-
Fast High-Impedance Spectroscopy Method Using SINC Signal Excitation
PublikacjaIn this paper the method of fast impedance spectroscopy of technical objects with high impedance (|Zx| > 1 Gohm) is evaluated by means of simulation and practical experiment. The method is based on excitation of an object with a sinc signal and sampling response signals proportional to current flowing through and voltage across the measured impedance. The object impedance spectrum is obtained with use of continuous Fourier transform...
-
Identification of Non-stationary and Non-linear Drying Processes
Publikacja -
Detection of Delamination in Laminate Wind Turbine Blades Using One-Dimensional Wavelet Analysis of Modal Responses
PublikacjaThis paper demonstrates the effectiveness of a nondestructive diagnostic technique used to determine the location and size of delamination in laminated coatings of wind turbine blades. This is realized based on results of numerical and experimental investigations obtained by the use of the finite element method (FEM) and laser scanning vibrometry (LSV). The proposed method is based on the one-dimensional continuous wavelet transform...
-
Respiration rate estimation using non-linear observers in application to wastewater treatment plant
PublikacjaA problem of respiration rate estimation using two new non-linear observers for a wastewater treatment plant is addressed in this paper. In particular, a non-linear adaptive Luenberger-like observer and a super twisting sliding mode observer have been derived to produce stable and bounded estimates of the respiration rate. During the synthesis of the particular observer, an appropriate mathematical utility model was used. The observability...
-
On modelling and non-linear elasto-plastic analysis of thin shells with deformable junctions
PublikacjaThe undeformed base surface of the irregular thin shell is modelled by the union of a finite number of regular smooth surface elements joined together along spatial curvilinear surface edges. The equilibrium conditions are formulated by postulating an appropriate form of the principle of virtual work, where also deformability of shell junctions is taken into account. The PVW is then discretised by C1 finite elements and the incremental-iterative...
-
Extended non-linear relations of elastic shells undergoing phase transitions
PublikacjaThe non-linear theory of elastic shells undergoing phase transitions was proposed by two first authors in J. Elast. 79, 67-86 (2004). In the present paper the theory is extended by taking into account also the elastic strain energy density of the curvilinear phase interface as well as the resultant forces and couples acting along the interface surface curve itself. All shell relations are found from the variational principle of...
-
Analysis of turnouts with non-linear curvature of diverging track for different train running speeds
PublikacjaThe paper deals with the issue of shaping a variable curvature in the diverging track of the railway turnout. Solution without a circular arc in the central zone, comprising two zones of non-linear curvature, of the same length, having zero curvature values at the end points, was adopted as a model, on the basis of the previously conducted dynamic tests. Optimum type of curvature was selected from the point of view of the kinematic...
-
Development of linear projecting in studies of non-linear flow. Acoustic heating induced by non-periodic sound
PublikacjaRównanie bilansu energii rozkłada się na sumę dwóch równań, opisujących dynamikę fali akustycznej i wywołanego przez nią ogrzewania. Nowe równanie dynamiczne stosowane jest dla opisu dźwięku nieokresowego zarówno jak okresowego. Rozpatruje się geometrię wiązkową. Omówiane są poszczególne udziały przewodnictwa cieplnego i lepkości w ogrzewaniu akustycznym. Równania stanu ośrodka propagacji są uwzględniane w najbardziej ogólnej postaci.
-
Firing map of an almost periodic input function
PublikacjaIn mathematical biology and the theory of electric networks the firing map of an integrate-and-fire system is a notion of importance. In order to prove useful properties of this map authors of previous papers assumed that the stimulus function f of the system ẋ = f(t,x) is continuous and usually periodic in the time variable. In this work we show that the required properties of the firing map for the simplified model ẋ = f(t) still...
-
Features of load and wear of main propulsion devices on sea-going ships with piston combustion engines and their impact on changes in technical states of the systems
PublikacjaThe paper presents the specificity of operation of propulsion systems of seagoing ships which causes the need to control the load on them, especially on their engines called main engines. The characteristics of the load on the propulsion systems, especially on the main engines as well as on the shaft lines and propellers driven by the engines, along with the process of wear in tribological joints (sliding tribological systems)...
-
TIME- AND FREQUENCY-DOMAIN QUASI-2D SMALL-SIGNAL MOSFET MODELS
PublikacjaA novel approach to small-signal MOSFET modeling is presented in this book. As a result, time- and frequency-domain physics-based quasi-2D NQS four-terminal small-signal MOSFET models are proposed. The time-domain model provides the background to a novel DIBL-included quasi‑2D NQS four-terminal frequency-domain small-signal MOSFET model. Parameters and electrical quantities of the frequency-domain model are described by explicit...
-
Drilling couples and refined constitutive equations in the resultant geometrically non-linear theory of elastic shells
PublikacjaIt is well known that distribution of displacements through the shell thickness is non-linear, in general. We introduce a modified polar decomposition of shell deformation gradient and a vector of deviation from the linear displacement distribution. When strains are assumed to be small, this allows one to propose an explicit definition of the drilling couples which is proportional to tangential components of the deviation vector....
-
Selective H2 production from plastic waste through pyrolysis and in-line oxidative steam reforming
PublikacjaThis study deals with the proposal of pyrolysis and in-line oxidative steam reforming (P-OSR) for plastic waste valorization and assesses the potential of this strategy for the selective production of H2. Overall, the study aims at progressing towards the fine-tuning of the pyrolysis-reforming technology by co-feeding O2. Thus, a multi-point O2 injection system has been developed to ensure a suitable O2 distribution in the reforming...
-
Approximation of the non-linear roll damping
PublikacjaArtykuł omawia, jak otrzymać oszacowanie nieliniowego momentu tłumiącehgo kołysania boczne okretu za pomocą zapisu przebiegu kołysań swobodnych modelu okrętu. Udowadnia, że 1) moment tłumiący w kategoriach aproksymacji jest nieanalityczną funkcją nieparzystą prędkosci kołysań, 2) standardowa metoda, oparta na stosunku dwóch kolejnych amplitud, ma ograniczone zastosowanie, do niezbyt dużych amplitud kołysań. Zaproponowano nową metodą...
-
Linear-scaling calculation of Hartree-Fock exchange energy with Non-orthogonal Generalised Wannier Functions
PublikacjaWe present a method for the calculation of four-centre two-electron repulsion integrals in terms of localised non-orthogonal generalised Wannier functions (NGWFs). Our method has been imple- mented in the ONETEP program and is used to compute the Hartree-Fock exchange energy component of Hartree-Fock and Density Functional Theory (DFT) calculations with hybrid exchange-correlation functionals. As the NGWFs are optimised in situ...
-
The Latest Advances in Wireless Communication in Aviation, Wind Turbines and Bridges
PublikacjaPresent-day technologies used in SHM (Structural Health Monitoring) systems in many implementations are based on wireless sensor networks (WSN). In the context of the continuous development of these systems, the costs of the elements that form the monitoring system are decreasing. In this situation, the challenge is to select the optimal number of sensors and the network architecture, depending on the wireless system’s other parameters...
-
Centrifuge modelling of tapered wall jacked into dense sand
PublikacjaA series of static penetration tests of trapezoidal walls in dense Fontainebleau sand were performed in the geotechnical centrifuge at Gustave Eiffel University. The models of wall with three different shapes (straight profile with thickness D=16mm, 0.75 degree and 1.5 degree of taper angle) but with the same volume were used. The soil mass was instrumented with five stress cells located at two levels at 2D, 4D and 6D distance...
-
Investigation of buckling resistance of columns using non-linear static and dynamic analysis
PublikacjaThe aim of this paper is to investigate the stability process in an axially compressed column using a static and dynamic finite element analysis by taking both the geometric and material non-linearity into account. The perfect column and column with geometric imperfections were analysed. The linear buckling analyses were used to obtain the lowest buckling load and shapes of buckled forms that were taken into account as initial...
-
Low temperature growth of diamond films on optical fibers using Linear Antenna CVD system
PublikacjaIt is not trivial to achieve a good quality diamond-coated fibre interface due to a large difference in the properties and composition of the diamond films (or use coating even) and the optical fibre material, i.e. fused silica. One of the biggest problems is the high temperature during the deposition which influences the optical fibre or optical fibre sensor structure (e.g. long-period gratings (LPG)). The greatest advantage of...
-
Estimation of a Stochastic Burgers' Equation Using an Ensemble Kalman Filter
PublikacjaIn this work, we consider a difficult problem of state estimation of nonlinear stochastic partial differential equations (SPDE) based on uncertain measurements. The presented solution uses the method of lines (MoL), which allows us to discretize a stochastic partial differential equation in a spatial dimension and represent it as a system of coupled continuous-time ordinary stochastic differential equations (SDE). For such a system...
-
Non-linear behaviour of base-isolated building supported on flexible soil under damaging earthquakes
PublikacjaSeismic isolation is a strategy to reduce damage of structures exposed to devastating earthquake excitations. Isolation systems, applied at the base of buildings, lower the fundamental frequency of the structure below the range of dominant frequencies of the ground motion as well as allow to dissipate more energy during structural vibrations. The effectiveness of the base-isolated buildings in damage reduction has been confirmed...
-
A model of fuel combustion process in the marine reciprocating engine work space taking into account load and wear of crankshaft-piston assembly and the theory of semi-Markov processes
PublikacjaThe ar ticle analyses the operation of reciprocal internal combu stion engines, with mar ine engines u sed a s an example. The analysis takes into account types of energy conversion in the work spaces (cylinders) of these engines, loads of their crankshaft-piston assemblies, and types of fuel combustion which can take place in these spaces during engine operation. It is highlighted that the analysed time-dependent loads of marine...
-
The effects of different aeration modes on ammonia removal from sludge digester liquors in the nitritation–anammox proces
PublikacjaThe aim of this study was to determine the impact of continuous and intermittent aeration on the rate of ammonia removal in the combined nitritation–anammox process. This process was run in two parallel sequencing batch reactors (SBRs), with a working volume V = 10 L, treating sludge digester liquors from the Gdansk (Poland) wastewater treatment plant (WWTP). The ammonia oxidizing bacteria were cultivated from activated sludge...
-
Short-Term Observations of Rainfall Chemistry Composition in Bellsund (SW Spitsbergen, Svalbard)
PublikacjaGlobal warming results in increasingly widespread wildfires, mostly in Siberia, but also in North America and Europe, which are responsible for the uncontrollable emission of pollutants, also to the High Arctic region. This study examines 11 samples of rainfall collected in August in a coastal area of southern Bellsund (Svalbard, Norway). It covers detailed analysis of major ions (i.e., Cl−, NO3−, and SO42−) and elements (i.e.,...
-
Discrete and continuous fractional persistence problems – the positivity property and applications
PublikacjaIn this article, we study the continuous and discrete fractional persistence problem which looks for the persistence of properties of a given classical (α=1) differential equation in the fractional case (here using fractional Caputo’s derivatives) and the numerical scheme which are associated (here with discrete Grünwald–Letnikov derivatives). Our main concerns are positivity, order preserving ,equilibrium points and stability...
-
Oznaczanie tlenu – od metody Winklera do czujników enzymatycznych (Determination of oxygen – from Winkler Method to enzymatic sensor)
PublikacjaMonitoring of dioxygen levels is of utmost importance from the view-point of life processes, medical diagnostics, nutrition and chemical industries. In all these measurements both low and high levels of this element are important. The common methods for the determination of dioxygen are the Winkler method, Clark electrode and pulsoxymeters. A new, already strong field of research can be now recognized – the development of miniaturized...
-
Three-dimensional geographically weighted inverse regression (3GWR) model for satellite derived bathymetry using Sentinel-2 observations
PublikacjaCurrent trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favourable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment...
-
Large‐Scale Traveling Ionospheric Disturbances Over the European Sector During the Geomagnetic Storm on March 23–24, 2023: Energy Deposition in the Source Regions and the Propagation Characteristics
PublikacjaMultiple Large-Scale Traveling Ionospheric Disturbances (LSTIDs) are observed in the European sector in both day-time and night-time during the magnetic storm on March 23–24, 2023. The Total Electron Content (TEC) observation from a network of GNSS receivers shows the propagation of LSTIDs with amplitudes between around 0.5 and 1 TECU originating from auroral and polar cusp regions down to southern Europe (35°N) with velocities...
-
A significance of multi slip condition for inclined MHD nano-fluid flow with non linear thermal radiations, Dufuor and Sorrot, and chemically reactive bio-convection effect
PublikacjaThe aim of this research is to discuss the significance of slip conditions for magnetized nanofluid flow with the impact of nonlinear thermal radiations, activation energy, inclined MHD, sorrot and dufour, and gyrotactic micro motile organisms over continuous stretching of a two-dimensional sheet. The governing equations emerge in the form of partial differential equations. Since the resultant governing differential equations...
-
A framework for risk matrix design: A case of MASS navigation risk
PublikacjaRisk matrix, a tool for visualizing risk assessment results, is essential to facilitate the risk communication and risk management in risk-based decision-making processes related to new and unexplored socio-technical systems. The use of an appropriate risk matrix is discussed in the literature, but it is overlooked for emerging technologies such as Maritime Autonomous Surface Ships (MASS). In this study, a comprehensive framework...
-
Response of a New Low-Coherence Fabry-Perot Sensor to Hematocrit Levels in Human Blood
PublikacjaIn this paper, a low-coherence Fabry-Perot sensor with a spectrally measured signal processing response to the refractive index of liquids is presented. Optical fiber sensors are potentially capable of continuous measuring hematocrit levels in blood. Low-coherence Fabry-Perot interferometric sensors offer a robust solution, where information about the measurand is encoded in the full spectrum of light reflected from the sensing...
-
Linear game non-contextuality and Bell inequalities—a graph-theoretic approach
PublikacjaWe study the classical and quantum values of a class of one-and two-party unique games, that generalizes the well-known XOR games to the case of non-binary outcomes. In the bipartite case the generalized XOR(XOR-d) games we study are a subclass of the well-known linear games. We introduce a 'constraint graph' associated to such a game, with the constraints defining the game represented by an edge-coloring of the graph. We use the...
-
Non-Destructive Diagnostics of Concrete Beams Strengthened with Steel Plates Using Modal Analysis and Wavelet Transform
PublikacjaExternally bonded reinforcements are commonly and widely used in civil engineering objects made of concrete to increase the structure load capacity or to minimize the negative effects of long-term operation and possible defects. The quality of adhesive bonding between a strengthened structure and steel or composite elements is essential for effective reinforcement; therefore, there is a need for non-destructive diagnostics of adhesive...