Search
Filters
total: 1716
filtered: 1546
displaying 1000 best results Help
Search results for: MEAN SYSTEM LOSS MODEL
-
Flow through a prosthetic mechanical aortic valve: Numerical model and experimental study
PublicationThis research presents a numerical model dedicated for virtual patient diagnostics in the field of synthetic valve implantation. The model operates based on computational fluid dynamics solver with implemented rigid body motion solver. Characteristic indicators related to the prosthetic valve were determined to assess the correctness of cardiac system operation after implantation. A novel approach for dynamic time discretization...
-
The Smith-Watson-Topper parameter and fracture surface topography relationship for additively manufactured 18Ni300 steel subjected to uniaxial variable-amplitude loading
PublicationIn this paper, the association between Smith-Watson-Topper (SWT) parameter and fracture surface topography is studied in additively manufactured maraging steel exposed to variable-amplitude fatigue loading. The post-failure fracture surfaces were examined using a non-contact 3D surface topography measuring system and the entire fracture surface method. The focal point is on the correspondence between fatigue characteristics, articulate...
-
Method of selecting the LS-SVM algorithm parameters in gas detection process
PublicationIn this paper we showed the method of resistive gas sensors data processing. The UV irradiation and temperature modulation was applied to improve gas sensors’ selectivity and sensitivity. Noise voltage across the sensor’s terminals (proportional to its resistance fluctuations) was recorded to estimate power spectral density. This function was an input data vector for LS-SVM (least squares – support vector machine) algorithm, which...
-
Thermal and technological aspects of double face grinding of C45 carbon steel
PublicationIn grinding, the contact zone temperature is a decisive factor influencing the achievable surface quality and the grinding tool wear. In contrast to other grinding processes, only few information regarding double face grinding with planetary kinematics when processing steel is known up to date. Since the successive substitution of in-dustrial double-sided lapping processes by double-sided grinding, it has become necessary to the...
-
Evaluation of the significance of the effect of the active cross-sectional area of the inlet air channel on the specific enthalpy of the exhaust gas of a diesel engine using statistics F of the Fisher-Snedecor distribution
PublicationThis paper presents the application of Fisher-Snedecor distribution F statistics to assess the significance of the influence of changes in the active cross-sectional area of the inlet air channel (Adol) flow in a diesel engine on the observed diagnostic parameter determined on the basis of measurements of the quick changing exhaust gas temperature in the outlet channel, which is the specific enthalpy of the exhaust gas stream within...
-
Stress–strain model of lower corroded steel plates of normal strength for fitness-for-purpose analyses
PublicationThis study investigates the mechanical properties of specimens made of normal strength steel subjected to lower marine immersed corrosion degradation levels (below 25 %). The specimens were corroded in laboratory conditions, and only natural factors were controlled to raise the corrosion rate (reaching the level of 1 mm/year). Three different thicknesses of plates made of normal strength of shipbuilding steel are investigated (between...
-
Greedy Multipoint Model-Order Reduction Technique for Fast Computation of Scattering Parameters of Electromagnetic Systems
PublicationThis paper attempts to develop a new automated multipoint model-order reduction (MOR) technique, based on matching moments of the system input–output function, which would be suited for fast and accurate computation of scattering parameters for electromagnetic (EM) systems over a wide frequency band. To this end, two questions are addressed. Firstly, the cost of the wideband reduced model generation is optimized by automating a...
-
Numerical evaluation of dynamic response of an experimentally tested base-isolated and fixed-base steel structure model
PublicationSeismic isolation is recognized as one of the most popular and effective methods of protecting structures during earthquake. The present paper is focused on the comparison be-tween the dynamic responses of buildings with fixed and isolated bases exposed to seismic exci-tations. The aim of the study is to investigate the effectiveness of a simplified base isolation numerical modelling technique using the linear springs. One-storey...
-
Soft Sensor Application in Identification of the Activated Sludge Bulking Considering the Technological and Economical Aspects of Smart Systems Functioning
PublicationThe paper presented the methodology for the construction of a soft sensor used for activated sludge bulking identification. Devising such solutions fits within the current trends and development of a smart system and infrastructure within smart cities. In order to optimize the selection of the data-mining method depending on the data collected within a wastewater treatment plant (WWTP), a number of methods were considered, including:...
-
Firing map of an almost periodic input function
PublicationIn 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...
-
Emotion monitoring system for drivers
PublicationThis article describes a new approach to the issue of building a driver monitoring system. Actual systems focus, for example, on tracking eyelid and eyebrow movements that result from fatigue. We propose a different approach based on monitoring the state of emotions. Such a system assumes that by using the emotion model based on our own concept, referred to as the reverse Plutchik’s paraboloid of emotions, the recognition of emotions...
-
Optical glyphs based localization and identification system
PublicationThe paper presents a description of functioning of a platform supporting the detection of obstructive diseases in the respiratory system education process. A 16-parameter model of the respiratory system simulated in the MATLAB/Simulink environment was set in the role of the tested patient. It has been linked to the control layer, developed in the LabVIEW environment, using the SIT library (Simulation Interface Toolkit). This layer...
-
An application supporting the educational process of the respiratory system obstructive diseases detection
PublicationThe paper presents a description of functioning of a platform supporting the detection of obstructive diseases in the respiratory system education process. A 16-parameter model of the respiratory system simulated in the MATLAB/Simulink environment was set in the role of the tested patient. It has been linked to the control layer, developed in the LabVIEW environment, using the SIT library (Simulation Interface Toolkit). This layer...
-
Flood Modelling and Risk Analysis of Cinan Feizuo Flood Protection Area, Huaihe River Basin
PublicationThis study evaluated multiple aspects of flood risks and effects on the Cinan Feizuo flood protection area in the Huaihe River basin. Flooding remains a leading problem for infrastructure, especially in urban, residential areas of the region. Effective flood modeling for urbanized floodplains is challenging, but MIKE (ID-2D) is paramount for analyzing and quantifying the risk in the vulnerable region. The Saint-Venant equation...
-
Test loadings of arch bridges
PublicationIn Poland an appreciable developement of bridge building can be seen in recent years. Arch structures are more and more common, because of the original geometrical and aesthetical form, aside with explicit structural system. Paper concerns the applied computational conceptions and researches on an example of two arch bridges. The goal of the studies is to check the correctness of the real construction work and design assumptions,...
-
Using contextual conditional preferences for recommendation taska: a case study in the movie domain
PublicationRecommendation engines aim to propose users items they are interested in by looking at the user interaction with a system. However, individual interests may be drastically influenced by the context in which decisions are taken. We present an attempt to model user interests via a set of contextual conditional preferences. We show that usage of proposed preferences gives reasonable values of the accuracy and the precision even when...
-
Reduction of steel chimney vibrations with a pendlum damper.
PublicationKarman vortices observed around chimneys may induce dangerous structural vi-brations at certain wind velocities. The aim of this paper is to analyse theeffectiveness of pendulum damper in vibration reduction of a steel chimney. A two degree-of-freedom system is used to model the behaviour of the struc-ture equipped with a damper. The results of the study show that the use of pendulum with tuned frequency leads to significant...
-
Calculation of self and mutual inductances of the switched reluctance machine mathematical model.
PublicationA mathematical model of the switched reluctance machine (SRM) in a drive system obtained using Lagrange's energy method and a method of calculation of self and mutual inductances of the SRM are presented in the paper. The self and mutual inductances are elements of Lagrange's function in generalised coordinates and have been calculated using the finite element method (FEM). Selected calculation results for the particular machine...
-
Analiza możliwości zastosowania środowiska SCILAB do wspomagania projektowania podsystemów energetycznych statków = Analysis of capability of using SCILAB for adding design of power ship subsystems
PublicationW artykule przedstawiono koncepcję wykorzystania środowiska symulacyjnego Scilab, modeli matematycznych oraz badań symulacyjnych przy projektowaniu podsystemów energetycznych statku. Zredagowano przykładową strukturę zawierającą model wysokoprężnego silnika oraz model śruby okrętowej. Przedstawione procedury oraz modele matematyczne zostaną włączone do systemu ekspertowego wspomagającego projektowanie statków. This paper deals...
-
Modelling of Mechatronic Systems with Distributed Parameter Components
PublicationThe paper presents an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of distributed system has been defined by application of the bond graph methodology and the distributed transfer function method (DTFM). The proposed method of modelling enables to formulate input data for computer analysis by application of the DTFM. The computational package for the analysis of complex...
-
Mixed, quantum-classical description of electron density transfer in the collision process
PublicationIn this work, we investigate an ion-atom model describing the time-dependent evolution of electron density during the collision. For a S3+- H system, numerical simulations are based on classical trajectory calculations, and the electron density behaviour is described with the time-dependent Schrödinger equation. We apply the finite difference method to obtain quantitative insights into the charge transfer dynamics, providing detailed...
-
On the Equations of the Surface Elasticity Model Based on the Theory of Polymeric Brushes
PublicationMotivating by theory of polymers, in particular, by the models of polymeric brushes we present here the homogenized (continual) two-dimensional (2D) model of surface elasticity. A polymeric brush consists of an system of almost aligned rigid polymeric chains. The interaction between chain links are described through Stockmayer potential, which take into account also dipole-dipole interactions. The presented 2D model can be treated...
-
THE COMPOSITION MODULATION EFFECT IN GaInPAs SOLID SOLUTIONS AS A MANIFESTATION OF ENERGY RESONANCE AFTER MATERIAL'S SPINODAL DECOMPOSITION
PublicationThe Cahn-Hilliard model concepts are extended to describe the spinodal decomposition of Ga$_x$In$_{1-x}$P$_y$As$_{1-y}$ solid solutions grown on the InP substrate. The energy of elastic deformation of the thin layer of a solid solution was calculated on the assumption of its coherent conjugation with the massive InP substrate. The excess energy of component mixing in the solid phase was modeled in accordance with the simple solution...
-
Improving automatic surveillance by sound analysis
PublicationAn automatic surveillance system, based on event detection in the video image can be improved by implementing algorithms for audio analysis. Dangerous or illegal actions are often connected with distinctive sound events like screams or sudden bursts of energy. A method for detection and classification of alarming sound events is presented. Detection is based on the observation of sudden changes in sound level in distinctive sub-bands...
-
Estimation of the Regenerative Braking Process Efficiency in Electric Vehicles
PublicationIn electric and hybrid vehicles, it is possible to recover energy from the braking process and reuse it to drive the vehicle using the batteries installed on-board. In the conditions of city traffic, the energy dissipated in the braking process constitutes a very large share of the total resistance to vehicle motion. Efficient use of the energy from the braking process enables a significant reduction of fuel and electricity consumption...
-
Kontekstowo zorientowany model bezpieczeństwa systemów internetowych
PublicationW rozprawie dokonano analizy usługowych systemów internetowych pod względem bezpieczeństwa. Przedstawiono autorskie uniwersalne modele bezpieczeństwa CoRBAC oraz jego rozszerzenie TCoRBAC, będące rozwinięciem tradycyjnego modelu RBAC. Uwzględniono analizę szeroko rozumianego kontekstu funkcjonowania systemu oraz poziom jego zaufania do użytkownika. Opracowano metodę wyznaczania dwóch parametrów: zaufania do systemu (λ) będącego...
-
An optimized dissolved oxygen concentration control in SBR with the use of adaptive and predictive control schemes
PublicationThis paper addresses the problem of optimizing control of the aeration process in a water resource recovery facility (WRRF) using sequencing batch reactor (SBR), one that affects the efficiency of wastewater treatment by stimulating metabolic reactions of microorganisms through dissolved oxygen (DO) level control, and accounts for the predominant part of operating costs. Two independent approaches to DO control algorithm design...
-
Hierarchical dissolved oxygen control for activated sludge processes
PublicationA hierarchical controller for tracking the dissolved oxygen reference trajectory in activated sludge processes is proposed and investigated. The removal of nitrogen and phosphorous from wastewater is considered. Typically, an aeration system itself is a complicated hybrid nonlinear dynamical system with faster dynamics compared to the internal dynamics of the dissolved oxygen in a biological reactor. It is a common approach to...
-
Experimental and numerical study of thermal and electrical potential of BIPV/T collector in the form of air-cooled photovoltaic roof tile
PublicationAmong renewable energy sources, Building-Integrated Photovoltaic/Thermal (BIPV/T) systems are gaining increasing interest. To improve their economic competitiveness, technologies that increase their efficiency are searched for. The paper is devoted to evaluating the impact of various air-cooling configurations on the thermal and electrical performance of a photovoltaic roof tile. A numerical model of the own experimental system...
-
Fully Tunable Analog Biquadratic Filter for Low-Power Auditory Signal Processing in CMOS Technologies
PublicationA novel Gm-C structure of a second-order continuous-time filter is proposed that allows for the independent control of the filter’s natural frequency (ω0) and quality factor (Q). The structure consists of two capacitors and four transconductors. Two transconductors together with the capacitors form a lossless second-order circuit with tunable ω0. The other two transconductors form a variable gain amplifier (VGA) which realizes...
-
Application of Galvanostatic Non-Linear Impedance Spectroscopy to the Analysis of Metallic Material Degradation
PublicationThis study presents a novel application of Non-Linear Electrochemical Impedance Spectroscopy (NLEIS) in galvanostatic mode for the rapid, non-destructive assessment of metal degradation. By using galvanostatic mode instead of traditional potentiostatic methods, polarization-related challenges are mitigated, enabling more accurate and reliable analysis. The technique allows for the determination of corrosion rates (corrosion current)...
-
New Method of Non-Linear Electrochemical Impedance Spectroscopy with an Amplitude-Modulated Perturbation Signal
PublicationThe paper presents a new method of non-linear electrochemical impedance spectroscopy (NLEIS), which allows fast and nondestructive evaluation of the corrosion rate and determination of the Tafel coefficients values for a corrosion system under investigation. This method employs amplitude modulation of the ac perturbation signal. The study demonstrated that it was possible to obtain impedance characteristic as a function of the...
-
A Hyperdense Semantic Domain for Discontinuous Behavior in Physical System Models
PublicationMultiple time models have been proposed for the formalization of hybrid dynamic system behavior. The superdense notion of time is a well-known time model for describing event-based systems where several events can occur simultaneously. Hyperreals provide a domain for defining the semantics of hybrid models that is elegantly aligned with first principles in physics. This paper discusses the value of both time models and shows how...
-
Sensorless Multiscalar Control of Five-Phase Induction Machine with Inverter Output Filter
PublicationThe paper presents a complete solution for speed sensorless control system for five-phase induction motor with voltage inverter, LC filter and nonlinear control of combined fundamental and third harmonic flux distribution. The control principle, also known as multiscalar control, nonlinear control or natural variables control, is based on a use of properly selected scalar variables in control feedback to linearize controlled system....
-
Modeling two phase flow in large scale fractured porous media with an extended multiple interacting continua method
PublicationWe present a two phase flow conceptual model, the corresponding simulator (2pMINC) and a workflow for large-scale fractured reservoirs, based on a continuum fracture approach which uses the multiple interacting continua (MINC) method complemented with an improved upscaling technique. The complex transient behavior of the flow processes in fractured porous media is captured by subgridding the coarse blocks in nested volume elements...
-
THE MODELLING OF ACCUMULATION AND DISSIPATION OF ENERGY IN MECHANICAL DRIVE SYSTEM
PublicationThis paper presents a modelling of accumulation and dissipation energy in simple drive system. The simple drive system is presented by laboratory stand designed for calculate fatigue life of material for bending and rotation tests pieces. The laboratory stand was prepared to diagnosis of fatigue life of material by use energetic methods. This idea was submitted as utility model to Polish Patent Office. This laboratory stand gives...
-
Fuctional structure of diagnostic system for wheeled tractors
PublicationAn application of computer controlled fuel injection systems in vehicle engines and growing demands concerning toxic substances emission and fuel consumption was a main reason for OBD (On Board Diagnosis) development. In spite of a great technological development, only some tractors are equipped in diagnostic systems. On board diagnosis is strongly connected with emission demands and does not concern other important vehicle functions.In...
-
Pre-swirl energy saving device in marine application
PublicationThis paper covers topics of energy saving device (ESD) with application to marine propulsors. The form of ESD, considered in this paper, consists of fixed lifting foils mounted in front of the screw propeller (the pre-swirl stator/guide vanes). An algorithm for designing propulsion systems, consisting of guide vanes and screw propeller, is presented. The proposed method relies on hybrid lifting line (guide vanes)-lifting surface...
-
Experimental investigation of joint with positive eccentricity in CFS truss
PublicationDue to technological restrictions, in the case of trusses made of CFS open cross-sections, positive eccentricities in the truss joints have become very frequent. Therefore studies concerning the load-bearing capacity of truss joints with positive eccentricity were undertaken. It was assumed that the resistance of cold-formed steel (CFS) open cross-section truss joints located on compression chords and with positive eccentricity...
-
Highly Miniaturized Self-Diplexed U-Shaped Slot Antenna Based on Shielded QMSIW
PublicationThis article presents an efficient yet simple design approach to highly miniaturized cavity-backed self-diplexing antenna (SDA) with high-isolation. The structure employs a shielded quarter-mode substrate integrated waveguide (QMSIW). Two U-shaped slots are engraved on the top conducting plane, which realize two frequency bands and significant size reduction. The slots are excited by two independent 50Ω orthogonal feed-lines to...
-
Degradation of Kinematic PPP of GNSS Stations in Central Europe Caused by Medium-Scale Traveling Ionospheric Disturbances During the St. Patrick’s Day 2015 Geomagnetic Storm
PublicationIn solar cycle 24, the strongest geomagnetic storm took place on March 17, 2015, when the geomagnetic activity index was as high as -223 nT. To verify the impact that the storm had on the Global Navigation Satellite System (GNSS)’s positioning accuracy and precision, we used 30-s observations from 15 reference stations located in Central Europe. For each of them, we applied kinematic precise point positioning (PPP) using gLAB software...
-
Aerodynamic Shape Optimization for Delaying Dynamic Stall of Airfoils by Regression Kriging
PublicationThe phenomenon of dynamic stall produce adverse aerodynamic loading which can adversely affect the structural strength and life of aerodynamic systems. Aerodynamic shape optimization (ASO) provides an effective approach for delaying and mitigating dynamic stall characteristics without the addition of auxiliary system. ASO, however, requires multiple evaluations time-consuming computational fluid dynamics models. Metamodel-based...
-
Interannual Variability of the GNSS Precipitable Water Vapor in the Global Tropics
PublicationThis paper addresses the subject of inter-annual variability of the tropical precipitable water vapor (PWV) derived from 18 years of global navigation satellite system (GNSS) observations. Non-linear trends of retrieved GNSS PWV were investigated using the singular spectrum analysis (SSA) along with various climate indices. For most of the analyzed stations (~49%) the GNSS PWV anomaly was related to the El Niño Southern Oscillation...
-
Detection of ferromagnetic objects in local magnetic anomaly of the Baltic Sea
PublicationIn geological researches several kinds of methods are applied to discovering the natural resources. Planes, helicopters and UAVs (UnmAnned Vehicle) are used in researches in large areas. The gravity, electromagnetic and magnetic methods, which are used in geological researches, are presented in this paper. The special attention was paid to magnetic systems installed on mobile platforms. The magnetic field of the Earth obtained...
-
Metodologiczne aspekty opisowego modelowania w naukach ekonomicznych
PublicationPrzedmiot badań ekonomicznych, jako system złożony, podlega modelowaniu. Etapy dekompozycji i jakościowego opisu modelowanego systemu, w tym systemu gospodarczego, są nieodzowne w prawidłowym prowadzeniu badań naukowych. Z drugiej strony modelowanie w ekonomii nie powinno być pozbawione matematycznego języka opisu, ponieważ konstruując model wyjaśniający, należy posługiwać się zarówno modelem opisowym, jak i sformalizowanym. Tak...
-
Akaike's final prediction error criterion revisited
PublicationWhen local identification of a nonstationary ARX system is carried out, two important decisions must be taken. First, one should decide upon the number of estimated parameters, i.e., on the model order. Second, one should choose the appropriate estimation bandwidth, related to the (effective) number of input-output data samples that will be used for identification/ tracking purposes. Failure to make the right decisions results...
-
Autoencoder application for anomaly detection in power consumption of lighting systems
PublicationDetecting energy consumption anomalies is a popular topic of industrial research, but there is a noticeable lack of research reported in the literature on energy consumption anomalies for road lighting systems. However, there is a need for such research because the lighting system, a key element of the Smart City concept, creates new monitoring opportunities and challenges. This paper examines algorithms based on the deep learning...
-
Rozmyte algorytmy diagnostyki układów sterowania procesami przemysłowymi - Przykład laboratoryjny
PublicationW niniejszej pracy prezentuje się przykład zastosowania algorytmów detekcji usterek opartych na modelach rozmytych w systemie diagnostyki układu laboratoryjnego trzech połączonych zbiorników. Pomimo prostoty realizowanej koncepcji układowej, system ten jest przykładem często występującego w praktyce złożonego procesu przemysłowego. W przeprowadzonych badaniach do oceny stanu procesu oraz realizacji zadań diagnostycznych wykorzystuje...
-
Assessment of the usefulness of bacterial cellulose produced by Gluconacetobacter xylinus E25 as a new biological implant
PublicationBionanocellulose (BNC) is a clear polymer produced by the bacterium Gluconacetobacter xylinus. In our current study, “Research on the use of bacterial nanocellulose (BNC) in regenerative medicine as a function of the biological implants in cardiac and vascular surgery”, we carried out material analysis, biochemical analysis, in vitro tests and in vivo animal model testing. In stage 1 of the project, we carried out physical and...
-
The hydrogen bond network structure within the hydration shell around simple osmolytes: Urea, tetramethylurea, and trimethylamine-N-oxide, investigated using both a fixed charge and a polarizable water model
PublicationDespite numerous experimental and computer simulation studies, a controversy still exists regarding the effect of osmolytes on the structure of surrounding water. There is a question, to what extent some of the contradictory results may arise from differences in potential models used to simulate the system or parameters employed to describe physical properties of the mixture and interpretation of the results. Bearing this in mind,...