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Search results for: MULTISCALAR MODEL
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Importance of model tests in design and operation of watercraft for example CTO
PublicationShip Hydromechanics Division is a specialized research and development department of Ship Design and Research Centre conducting tests and research in the field of hydromechanics, connected with design and operation of ships and other floating structures, in scope of: predictions, numerical analyses, designs of - hull shape optimized with respect to the ship’s functions with the application of modern design tools, screw propellers...
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Global Surrogate Modeling by Neural Network-Based Model Uncertainty
PublicationThis work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural network-based surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...
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A Bayesian regularization-backpropagation neural network model for peeling computations
PublicationA Bayesian regularization-backpropagation neural network (BRBPNN) model is employed to predict some aspects of the gecko spatula peeling, viz. the variation of the maximum normal and tangential pull-off forces and the resultant force angle at detachment with the peeling angle. K-fold cross validation is used to improve the effectiveness of the model. The input data is taken from finite element (FE) peeling results. The neural network...
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Binary-Encounter Model for Direct Ionization of Molecules by Positron-Impact
PublicationWe introduce two models for the computation of direct ionization cross sections by positron impact over a wide range of collision energies. The models are based on the binary-encounter-Bethe model and take into account an extension of the Wannier theory. The cross sections computed with these models show good agreement with experimental data. The extensions improve the agreement between theory and experiment for collision energies...
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Towards the Development of a Risk Model for Unmanned Vessels Design and Operations
PublicationAn unmanned merchant vessel seems to be escaping from the stage of idea exploration. Once the concept proofs its safety, it may become a part of maritime reality. Although the safety aspect of such a ship has been addressed by a handful of scholars, the problem remains open. This is mainly due to lack of knowledge regarding actual operational circumstances and design of unmanned ships, which are yet to be developed. In the...
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Investigation of Transmit and Receive Characteristics of Laboratory Model for the Parametric Echosounder
PublicationInvestigation and operation of devices based on nonlinear interaction of high-intensity waves have been carried out for several decades. However, it is still a new tool to study the properties of the water environment and especially the upper layers of the seabed. This paper describes the results of tests of the new device that is intended to be applied for sounding underwater areas. The device has been designed and built in collaboration with...
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Model of heat transfer in the stagnation point of rapidly evaporating microjet
PublicationThe paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 mikrometer respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling...
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A Model-Driven Solution for Development of Multimedia Stream Processing Applications
PublicationThis paper presents results of action research related to model-driven solutions in the area of multimedia stream processing. The practical problem to be solved was the need to support application developers who make their multimedia stream processing applications in a supercomputer environment. The solution consists of a domain-specific visual language for composing complex services from simple services called Multimedia Stream...
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A quasi-2D small-signal MOSFET model - main results
PublicationMain results stemming from a new quasi 2D non-quasi-static small-signal four-terminal model of the MOSFET are presented in this work. The model is experimentally verified up to 30 GHz.
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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A quasi-2D small-signal MOSFET model - main results
PublicationDynamic properties of the MOS transistor under small-signal excitation are determined by kinetic parameters of the carriers injected into the channel, i.e., the low-field mobility, velocity saturation, mobility at the quiescent-point (Q-point), longitudinal electric field in the channel, by dynamic properties of the channel, as well as by an electrical coupling between the perturbed carrier concentration in the channel and the...
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Model rozwoju kompetencji kierowniczych w małych firmach informatycznych
PublicationW referacie przedstawiono wyniki badania nad rozwojem kompetencji kierowniczych w małych firmach IT. Omówiono badania ankietowe służące określeniu ważności poszczególnych kompetencji z modelu ICB organizacji IPMA dla małych firm. Na podstawie wyników ankiet wyróżniono trzy klasy ważności kompetencji kierowniczych dla typowej małej firmy IT, którą scharakteryzowano. Opracowana klasyfikacja może być podstawą rozwiązania doradczego...
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Data Model Development for Security Information Sharing in Smart Grids
PublicationThe smart grid raises new security concerns which require novel solutions. It is commonly agreed that to protect the grid, the effective collaboration and information sharing between the relevant stakeholders is prerequisite. Developing a security information sharing platform for the smart grid is a new research direction which poses several challenges related to the highly distributed and heterogeneous character of the grid. In...
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Representation of magnetic hysteresis in a circuit model of a single-phase transformer
PublicationThe paper presents a mathematical model for the hysteresis phenomenon in a multi-winding single-phase core type transformer. The set of loop differential equations was developed for K-th winding transformer model where the flux linkages of each winding includes a flux common Φ to all windings as function of magneto motive force Θ of all windings. The first purpose of this paper is to determine a hysteresis nonlinearity involved...
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Static Model of Steam/Water Cycle for Thermal and Economic Analysis
PublicationThe thermodynamic efficiency of typical conventional and nuclear power plants is insufficient. A large amount of the generated heat is removed to the environment and regarded as a waste. A solution which is commonly used to increase the efficiency and profitability of the existing and planned power plants refers to cogeneration of heat and power. To prepare sophisticated thermodynamic and economic analyses, a precise static model...
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NUMERYCZNY MODEL OBLICZENIOWY OBIEGU TURBINY KLASY 300 MW
PublicationNiniejszy artykuł stanowi opis modelu obiegu cieplnego turbiny o mocy 360MW, utworzonego w preprocesorze numerycznego programu obliczeniowego onazwie DIAGAR. Zadaniem opisywanego modelu jest odtwarzanie zjawisk fizycznych zachodzących w poszczególnych urządzeniach składowych obiegu, zarówno podczas poprawnej (sprawnej) pracy bloku energetycznego, jak i w przypadku pojawienia się niesprawności. Utworzony...
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LABORATORYJNY MODEL ODBIORNIKA DUŻEJ MOCY. KONCEPCJA, WYKONANIE, EKSPERYMENTY
PublicationW referacie przedstawiono koncepcję oraz sposób realizacji laboratoryjnego modelu odbioru o mocy 150 kVA. Odbiornik zaprojektowano w taki sposób aby umożliwić emulację zmienności mocy dowolnego odbiorcy, jak również pracę transformatora zasilającego takiego odbiorcę. W referacie zaprezentowano też przykładowe wyniki prób eksperymentalnych potwierdzające słuszność przyjętej koncepcji sterowania.
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Peculiarities associated with testing polyetheretherketone (PEEK) in a model rolling contact
PublicationPolyetheretherketone (PEEK) was investigated using a modified version of the four-ball tester in which the upper forth ball was replaced by a cone in such a way that kinematics of the four-ball configuration were fully preserved. Rotation of the cone enforced orbiting and rolling of the ceramic balls around the polymer cup. The results produced some unexpected peculiarities in the wear of ceramic balls which, in principle, should...
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Model dynamicznego balastowania małego morskiego obiektu typu stealth
PublicationW artykule przedstawiono podstawowe problemy związane z modelowaniem głównych cech decydujących o trudno-wykrywalności małego obiektu na etapie projektu koncepcyjnego. Metoda badawcza oparta jest na ocenie zachowania się obiektu i ocenie ryzyka wypadku. W artykule skupiono się głównie na przedstawieniu modelu matematycznego opisującego model dynamicznego balastowania małego morskiego obiektu typu stealth. Przedstawione w artykule...
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A Human Behaviour Model Agent for Testing of Voluntary Computing Systems
PublicationPaper presents a design and performance of a voluntary-based distributed computing system testing agent, implementing a human behaviour model. The agent, nicknamed iRobot, was designed and implemented to enable controlled, large scale testing of core algorithms of Comcute - a new voluntary distributed computing platform complementary to BOINC. The main agent design goals were: emulation of human behaviour when browsing web pages,...
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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MACRO MODEL OF SEAT BELT USE BY CAR DRIVERS AND PASSENGERS
PublicationThe article presents some problems of seat belt use by car drivers and passengers. It looks in particular at seat belt use and effectiveness in selected countries. Next, factors of seat belt use are presented and methodology of model development. A macro model of seat belt use is presented based on data from around fifty countries from different continents.
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Wirtualny model zbiorników z wodą w sterowniku PLC
PublicationModele obiektów rzeczywistych otrzymuje się na różnorodne sposoby i wykorzystuje w różnorodnych celach. Do badania obiektów automatyki stosuje się najczęściej programy komputerowe, np.: Matlab-Simulink, Scilab, GNU Octave, itp. Można również stosować pamięć operacyjną sterowników [1, 2]. W referacie przedstawiono opis wirtualnego modelu dwóch połączonych zbiorników z wodą w sterowniku PLC. Proste przekształcenia matematyczne pozwalają...
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A Quasi-2D MOSFET Model — 2D-to-Quasi-2D Transformation
PublicationA quasi-two-dimensional (quasi-2D) representation of the MOSFET channel is proposed in this work. The representation lays the foundations for a quasi 2D MOSFET model. The quasi 2D model is a result of a 2D into quasi 2D transformation. The basis for the transformation are an analysis of a current density vector field and such phenomena as Gradual Channel Detachment Effect (GCDE), Channel Thickness Modulation Effect (CTME), and...
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Model of the double-rotor induction motor in terms of electromagnetic differential
PublicationThe paper presents a concept, a construction, a circuit model and experimental results of the double-rotor induction motor. This type of a motor is to be implemented in the concept of the electromagnetic differential. At the same time it should fulfill the function of differential mechanism and the vehicle drive. One of the motor shafts is coupled to the direction changing mechanical transmission. The windings of the external rotor...
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An Empirical Model for the Polarisation Characteristics of Indoor Off-Body Channels
PublicationThis paper presents an analysis of the polarisation characteristics for the channel in dynamic off-body communications, and an empirical channel model, based on measurements performed at 2.45 GHz in an office environment. Body presence and propagation conditions have a strong influence on signal depolarisation. The model assumes three components for the total path loss: mean path loss, represented by a log-distance function with...
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Frequency-dependent coupling model for microwave band-pass filter
PublicationThe goal of this work was to create a circuit model which represents frequency-dependent coupling between microwave resonators. Our models are designed for in-line filters. The frequency-dependent coupling enables one to realize a transmission zero which is not possible in classical approach with frequency independent inverters. In addition, the proposed model allows us to observe out-of-band behavior, e.g. spurious resonance....
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Modified linear viscoelastic model of earthquake-induced structural pounding
PublicationIn recent times, earthquake-induced structural pounding has been intensively studied through the use of different impact force models. The numerical results obtained from the previous studies indicate that the linear viscoelastic model is relatively simple and accurate in modeling pounding-involved behavior of structures during earthquakes. The only shortcoming of the model is a negative value of the pounding force occurring just...
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An evaluation of effectiveness of fuzzy logic model in predicting the business bankruptcy
PublicationW artykule sprawdzono skuteczność pojedynczego modelu logiki rozmytej w prognozowaniu ryzyka upadłości przedsiębiorstw w Polsce. W badaniach wykorzystano wartości 14 wskaźników finansowych oraz ich dynamikę zmiany między pierwszym a drugim, drugim a trzecim oraz trzecim a czwartym rokiem objętymi analizą. We wnioskach omówiono różnicę w skutecznościach modelu uzyskanego na wartościach statycznych oraz dynamicznych wskaźników finansowych....
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Model instalacji napowietrzającej dla celów sterowania - studium przypadku
PublicationBiologiczne oczyszczanie ścieków stanowi podstawową grupę procesów w oczyszczalni ścieków. Jednym z nich jest napowietrzanie ścieków realizowane z wykorzystaniem instalacji napowietrzającej. Powszechnie uważa się go za jeden z najważniejszych i najdroższych procesów w oczyszczalni ścieków. Model procesu jest potrzebny do szczegółowej jego analizy, zbadania możliwości modyfikacji istniejących lub zastosowania innych metod sterowania....
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Antropoidalny Model Inteligentnego Systemu Decyzyjnego dla Jednostek Autonomicznych
PublicationGłównym celem pracy jest opracowanie modelu procesów psychologicznych -- od momentu otrzymania bodźca do momentu podjęcia adekwatnej reakcji -- zachodzących w mózgu człowieka (psychologia poznawcza), oraz teorii motywacji (potrzeb, popędów i emocji). Model, zaprezentowany w pracy nazwany Inteligentnym Systemem Decyzyjnym (ISD), może mieć zastosowanie w systemie sterowania jednostką autonomiczną (agentem). W rozprawie rozważa się...
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High-Precision FIR-Model-Based Dynamic Weighing System
PublicationConveyor belt-type checkweighers are increasingly popular components of modern production lines. They are used to assess the weight of the produced items in motion, i.e., without stopping them on the weighing platform. The main challenge one faces when designing a dynamic weighing system is providing high measurement accuracy, especially at high conveyor belt speeds. The approach proposed in this paper can be characterized as a...
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Model of an Integration Bus of Data and Ontologies of Smart Cities Processes
PublicationThis paper presents a model of an integration bus used in the design of Smart Cities system architectures. The model of such a bus becomes necessary when designing high-level architectures, within which the silo processes of the organization should be seen from the perspective of its ontology. For such a bus to be used by any city, a generic solution was proposed which can be implemented as a whole or in part depending on the requirements...
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Wideband Model Order Reduction for Macromodels in Finite Element Method
PublicationAbstract: This paper presents a novel algorithm for accelerating 3D Finite Element Method simulations by introducing macromodels created in local model order reduction in the selected subdomains of the computational domain. It generates the projection basis for a compact system of equations associated with a separate subdomain. Due to non-linear frequency dependency in the Right Hand Side (RHS), the standard reduction methods do...
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High-Level Model for the Design of KPIs for Smart Cities Systems
PublicationThe main goal of the paper is to build a high-level model for the design of KPIs. Currently, the development and processes of cities have been checked by KPI indicators. The authors realized that there is a limited usability of KPIs for both the users and IT specialists who are preparing them. Another observation was that the process of the implementation of Smart Cities systems is very complicated. Due to this the concept of a...
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Estimation of blood pressure parameters using ex-Gaussian model
PublicationThe paper presents an example of model-based estimation of blood pressure parameters (onset, systolic and diastolic pressure) from continuous measurements. First, the signal was low pass filtered and its quality was estimated. Good quality periods were divided into beats using an electrocardiogram. Next, the beginning of each beat of the blood pressure signal was approximated basing on the function created from the sum of two independent...
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Top k Recommendations using Contextual Conditional Preferences Model
PublicationRecommender systems are software tools and techniques which aim at suggesting to users items they might be interested in. Context-aware recommender systems are a particular category of recommender systems which exploit contextual information to provide more adequate recommendations. However, recommendation engines still suffer from the cold-start problem, namely where not enough information about users and their ratings is available....
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A MODEL FOR FORECASTING PM10 LEVELS WITH THE USE OF ARTIFICIAL NEURAL NETWORKS
PublicationThis work presents a method of forecasting the level of PM10 with the use of artificial neural networks. Current level of particulate matter and meteorological data was taken into account in the construction of the model (checked the correlation of each variable and the future level of PM10), and unidirectional networks were used to implement it due to their ease of learning. Then, the configuration of the network (built on the...
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Mechanical model of fascia-implant structure. Finite element simulation.
PublicationPraca dotyczy modelowania i symulacji syntetycznych implantów chirurgicznych stosowanych w leczeniu przepulin brzusznych metodą laparoskowpową. Prponowane są modele matematyczne a ich prawidłowość weryfikowana jest na podstawie badań doświadczalnych zachowania się modeli fizycznych wszczepionych implantów pod wpływem obciążeń wynikających z fizjologii człowieka. Nakreślona jest metodologia oceny trwałości połączenia siatki chirurgicznej...
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Reprezentation of mechanic hysteresis in a railway track using the Preisach model
PublicationThis paper presents an implementation of the classic scalar Preisach model to describe the hysteresis phenomenon created in a railway track subjected to lateral (in the horizontal plane) displacements. The principles of the Preisach theory and the scalar mathematical model of the mechanical hysteresis that is based on statistically distributed modified hysteresis operators are briefly presented. This article presents the characteristic...
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MODEL OF MULTILEVEL STOCHASTIC ANALYSIS OF ROAD SAFETY ON REGIONAL LEVEL
PublicationIn this paper multilevel approach to the issue of road safety level on the road network of European regions, classified as NUTS 2 in statistical databases of the European Union, has been presented. Following the pattern of many publications on road safety it has been assumed that the risk calculated as the number of death casualties in road accidents per 100,000 inhabitants of a given region has Poisson distribution. Therefore,...
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Topological-numerical analysis of a two-dimensional discrete neuron model
PublicationWe conduct computer-assisted analysis of a two-dimensional model of a neuron introduced by Chialvo in 1995 [Chaos, Solitons Fractals 5, 461–479]. We apply the method of rigorous analysis of global dynamics based on a set-oriented topological approach, introduced by Arai et al. in 2009 [SIAM J. Appl. Dyn. Syst. 8, 757–789] and improved and expanded afterward. Additionally, we introduce a new algorithm to analyze the return times...
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Experimental Verification of the CFD Model of the Squeeze Film Lifting Effect
PublicationAbstract: The presented study shows the results of the research into the squeeze film levitation phenomena. The system introduced in the investigation is composed of a vibrating surface, air squeeze film, and the surface of the body freely suspended over the film. The use of the CFD (Computational Fluid Dynamics) model used in the system allows us to determine the steady state, periodic behavior of the air film (described by Navier–Stokes,...
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A Numerical Model Study on Grasse River Ice Control Structures
PublicationIce jams in the Grasse River have caused the erosion of capping material designed to prevent the resurfacing of the bed sediment in the PCB-contaminated area. Two in-stream ice-control structures are proposed to avoid the jam-induced erosion of the capping material. These two ice-control options are a pier-type ice-control structure and a reconstruction of a small hydropower dam upstream of the capping site. A numerical model study...
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Model dynamiki sprężarki wirnikowej z regulowanymi łopatkami kierownicy
PublicationPrzedstawiono model dynamiki sprężarki wirnikowej turbiny gazowej współpracującej z siecią elektroenergetyczną. Model symuluje charakterystyki statyczne i dynamiczne sprężarki wirnikowej z regulowanym kątem nastawienia łopatek kierowniczych wlotowych. Za pomocą przedstawionego modelu dynamiki bloku elektroenergetycznego turbiny gazowej symulowano charakterystyki statyczne układu oraz charakterystyki dynamiczne. Odpowiedzi skokowe...
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Simple model of rain wind induced vibrations of stayed cables.
PublicationAnalizowano prosty, liniowy model drgań kabli mostów wantowych pod obciążeniem wiatrem i deszczem. Zakłada się, iż częstotliwość ruchu górnej kropli po powierzchni kabla i częstotliwość kabla są równe oraz iż amplituda ruchu kropli dla danej prędkości wiatru są stałe. Otrzymane rezultaty są porównane z istniejącymi w literaturze wynikami badań eksperymentalnych. Podaje się analityczne związki służące do oszacowania tłumienia...
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Efficient implementation of the Cauchy method for automated CAD-model construction.
PublicationW artykule przedstawiona została efektywna metoda konstrukcji wieloparametrycznych modeli układów mikrofalowych na podstawie wyników symulacji pełnofalowej. Algorytm wykorzystuje metodę najmniejszych kwadratów (TLS) do rozwiązania problemu interpolacyjnego i automatycznie dobiera rząd modelu.Przydatność i dokładność metody jest pokazana na przykładzie projektowania filtru z wykorzystaniem modeli trzech i pięciu zmiennych.
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Parametryczny, przestrzenny model silnika asynchronicznego - aplikacja programu AutoCad.
PublicationW pracy przedstawiono program komputerowy, który w sposób kompleksowy wspomaga użytkownika w automatycznym narysowaniu trójwymiarowego modelu silnika asynchronicznego klatkowego. Model maszyny jest parametryczny, co oznacza, że użytkownik definiuje topologię poszczególnych elementów na podstawie: wymiarów geometrycznych, typu łożyska, rodzaju uzwojenia, liczby żłobków itp. Zakres modelowania dotyczy silników indukcyjnych małej...
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Model filtru wyjściowego falownika napięcia w symulacji komputerowej.
PublicationW artykule przedstawiono układ z silnikiem asynchronicznym zasilanym z sieci elektroenergetycznej poprzez przemiennik częstotliwości z filtrem wyjściowym falownika napięcia. Zaproponowano nowy model filtru wyjściowego falownika napięcia połączonego z obwodem pośredniczącym przemiennika częstotliwości. Przy pomocy programu TCAD przeprowadzono analizę zamodelowanego układu. Dla badanego modelu filtru zamieszczono przebiegi prądów...
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Algebraic model of continuous time Gm-LC filters and applications.
PublicationW pracy zaprezentowano model algebraiczny filtrów Gm-LC czasu ciągłego i jego wybrane zastosowania. Zaproponowany model obejmuje struktury pracujące zarówno w trybie napięciowym jak i prądowym. Użyteczność opracowanego modelu potwierdzono na przykładzie syntezy eliptycznego filtru Gm-LC rzędu nieparzystego.