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Search results for: modelling
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Modelling and uncertainty in system analysis for safety assessment.
PublicationArtykuł obejmuje zagadnienia związane z modelowaniem i reprezentacją niepewności i ilościowych oszacowaniach ryzyka. Problem jest istotny w praktyce, ponieważ wystęopujhą wymagania przeprowadzenia ocen niepewności miar probabilistycznych i ryzyka. Dyskutuje się potencjalne żródła niepewności i dokonuje sie przeglądu podstaw teoretycznych reprezentacji niepewności. W modelowaniu systemów zawierających nieprecyzyjnie zdefiniowane...
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A nonlinear approach to modelling gas bubble deformation.
PublicationPrzedstawiono model wyjaśniający wpływ deformacji pęcherzyka na występowanie zjawiska chaosu podczas generowania pęcherzyków gazowych z pojedynczej dyszy zanurzonej w cieczy.
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Modelling of Flow Process in Small Diameter Tubes.
PublicationW pracy zastosowano standardowš korelację wrzenia w przepływie (wyprowadzonš dla rur o konwencjonalnych wymiarach) do przypadków wrzenia w rurach o małych rednicach. Porównanie wyników z danymi literaturowymi wykazało nieużytecznoć tej korelacji. Wykazano zatem potrzebę prowadzenia badań podstawowych celem uzyskania korelacji pozwalajšcej umiejętnie przewidywać warunki wymiany ciepła w kanałach o małych rednicach.
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Knowledge management and fuzzy modelling in software engineering
PublicationPraca zawiera rozdział poświecony problematyce budowy systemów z bazami wiedzy dla wspomagania procesów zarządzania. W rozdziale tym przedstawiono metody budowy systemów dla potrzeb zarządzania koncentrując uwagę na systemach opartych na wiedzy. Następnie omówiono możliwości zastosowania teorii zbiorów rozmytych do modelowania wiedzy. Na zakończenie przedstawiono przykład wykorzystania zbiorów rozmytych i systemów opartych na wiedzy...
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Modelling of bio-mechanical objects: recent examples
PublicationW opracowaniu przedstawiono dwa wykorzystania modelowania bio-mechanicznego wybranych obiektów: modelowanie zachowania mięśni w układzie ramię-przedramię oraz wstępny projekt protezy dłoni przy użyciu materiałów z pamięcią kształtu. Przedstawiono wyniki badań symulacyjnych oraz opis dynamiki działania układów sterowania dla protezy dłoni oraz dla układu ramię-przedramię.
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Wave Propagation Modelling in Composite Plates with Damages
PublicationW pracy przedstawiono model i wyniki analizy propagacji fali spręzystej w płycie kompozytowej z uszkodzeniami.
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On a 3D material modelling of smart nanocomposite structures
PublicationSmart composites (SCs) are utilized in electro-mechanical systems such as actuators and energy harvesters. Typically, thin-walled components such as beams, plates, and shells are employed as structural elements to achieve the mechanical behavior desired in these composites. SCs exhibit various advanced properties, ranging from lower order phenomena like piezoelectricity and piezomagneticity, to higher order effects including flexoelectricity...
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Advances in soft modelling techniques and decision support
PublicationPostępy w technikach miękkiego modelowania i wspomagania decyzji. W edytorialu przybliżono najnowsze osiągnięcia w zakresie miękkiego modelowania opartego na teorii zbiorów rozmytych i systemów z bazami wiedzy. Omówiono postępy teoretyczne w tej dziedzinie, jak również obszary obecnych i przyszłych zastosowań.
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Coupledfield modelling of interferometric hydrophone with self supportedmandrel.
PublicationW pracy przedstawiono nowatorską konstrukcję światłowodowego interferometrycznego przetwornika ciśnienia do zastosowań w hydrofonach. Przetwornik ten składa się z cewki światłowodowej zalanej w żywicy epoksydowej. Zaprezentowano technikę modelowania właściwości przetwornika, wykorzystującą opis przy pomocy parametrów równoważnego materiału ortotropowego i Metodę Elementów Skończonych. Przestawiono wyniki statycznego modelowania...
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Modelling EMI choke for the power electronics application
PublicationPrzedstawiono wyniki przeprowadzonych badań symulacyjnych i eksperymentalnych dotyczących propagacji zakłóceń elektromagnetycznych przewodzonych w dławikach przeciwzakłóceniowych stosowanych w przekształtnikach energoelektronicznych. Zaproponowany model obwodowy dławika pozwala na analizę symulacyjną właściwości w zakresie częstotliwości zaburzeń elektromagnetycznych przewodzonych. Model uwzględnia zjawiska związane z pojemnościami...
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FE modelling of brittle materials at the meso-scale
PublicationArtykuł omawia obliczanie lokalizacji odkształceń w elementach betonowych poddanych rozciąganiu. Obliczenia wykonano dla betonu na poziomie mezo. Obliczenia wykonano przy zastosowaniu modelu zniszczeniowego z degradacją sztywności rozszerzonego o nielokalność.
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Modelling of behavior of plain concrete using DEM
PublicationW artykule pokazano rozwój różnych zjawisk mikrostrukturalnych na poziomie kruszywa w betonie podczas jednoosiowego ściskania i rozciągania.. Obliczenia wykonano stosując metodę DEM. Wyniki na poziomie globalnym porównano doświadczalnymi. Szczególna uwagę zwrócono na propagację rys i szerokość lokalizacji odkształceń.
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Modelling the effect of composition on the tensile properties of concrete
PublicationRozdział omawia wyniki analizy mezoskopowej procesu pękania w betonie podczas zginania. Obliczenia wykonano na poziomie mezo wykorzystując model degradacji sztywności z nielokalnym osłabieniem. Zbadano wpływ właściwości kruszywa, stref przejściowych, nacięcia oraz długości charakterystycznej mikrostruktury na zachowanie sie betonu. Zaproponowano 2 metody określenia reprezentatywnego elementu objętościowego w betonie.
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Tackling Air Pollution in Cities with Modelling and Simulation: Remote Group Model Building as an Educational Tool Supporting System Dynamics Modelling
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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...
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Mechatronics design, modelling and controlling of the Stewart-Gough platform
PublicationThis paper presents a mechatronics design of a low cost Stewart-Gough platform (SGP) with rotary actuators. The designed SGP is supposed to be applied in a ball & plate control system. The synthesis of the ball & plate control system is also within the subject of the paper. A mechatronics design process of the SGP was conducted with computer-aided design (CAD) software. Unique analytical solutions of an inverse kinematics problem...
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Hysteresis modelling of a medium frequency single-phase transformer
PublicationThe article describes a feedback Preisach hysteresis model equivalent circuit implementation of a medium frequency single-phase transformer being a part of a high power and high efficiency DC-DC converter. The macroscopic models of magnetic hysteresis are introduced and the feedback Preisach model is selected for further analysis. The hysteresis model is developed for a prototype transformer and the hysteresis loops are compared...
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Port-Based Modelling of Distributed-Lumped Parameter Systems
PublicationThere in the paper is presented an uniform, port-based approach to modelling of both lumped and distributed parameter systems. Port-based model of the distributed system has been defined by application of bond graph methodology and distributed transfer function method (DTFM). The approach proposed combines versatility of port-based modelling and accuracy of distributed transfer function method. The concise representation of lumped-distributed...
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Modelling a 6-dof manipulator using Matlab software
PublicationThis paper presents an alternative approach to modelling a revolute robot. The manipulator in question is Kuka KR 16-2. The main problem in robot modelling is a kinematic analysis. The revolute robot consist of six rotary joints (6-DOF) with base, shoulder, elbow and wirst. The kinematics problem is defined as a transformation from the cartesian space to the joint space. The Denavit- Hartenberg (D-H) model of representation was...
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Selected problems of decision making modelling in power engineering
PublicationThe paper presents the selected problems of decision making modelling in power engineering specially investment risk evaluation methods. The proposed model can be used in the range programming the development and investing process in power engineering. Decision making problems in power engineering and the evaluation of investment effectiveness in particular are closely related to modelling which relatively accurately reflects...
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Advances in Modelling and Analysis of Strength of Corroded Ship Structures
PublicationThe present study reviews the recent advances in modelling and analyses the strength of corroded ship structures. Firstly, the time-variant methodologies that consider only the mean structural element thickness loss due to corrosion degradation are identified. Corrosion degradation is regarded as the phenomenon that causes uneven thinning of specimens. This has been captured by various researchers as the loss of mechanical properties...
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Modelling of dielectric properties of BiNbO4-based microwave ceramics
PublicationIn the present paper results of the studies devoted to computer simulations of dielectric response of electroceramics in a frequency domain as well as analysis of the experimental data are given. As an object of investigations BiNbO4-based microwave ceramics was taken. Simulations of the hypothetical impedance response of the ceramic system were performed under assumption of the brick-layer model. A strategy for analysis and modelling...
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Modelling of Abdominal Wall Under Uncertainty of Material Properties
PublicationThe paper concerns abdominal wall modelling. The accurate prediction and simulation of abdominal wall mechanics are important in the context of optimization of ventral hernia repair. The shell Finite Element model is considered, as the one which can be used in patient-specific approach due to relatively easy geometry generation. However, there are uncertainties in this issue, e.g. related to mechanical properties since the properties...
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Modelling of high frequency dynamic responses of engineering structures
PublicationModelling of high frequency dynamic responses of engineering structures, especially those related to wave propagation, is a real numerical challenge. Nowadays most of numerical models, used for that purpose, are based on the application of various finite element techniques. However, finite element discrete models may also be considered as possessing certain periodic structures, which may manifest themselves in particular scenarios....
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Analytical method of modelling the geometric system of communication route
PublicationThe paper presents a new analytical approach to modelling the curvature of a communication route by making use of differential equations. The method makes it possible to identify both linear and nonlinear curvature. It enables us to join curves of the same or opposite signs of curvature. Solutions of problems for linear change of curvature and selected variants of nonlinear curvature in polynomial and trigonometric form were analyzed....
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Path Loss Modelling in the Untypical Outdoor Propagation Environments
PublicationIn the paper three ways of path loss modelling in the untypical outdoor environments are presented. The exemplary untypical outdoor environment is analyzed. The investigated environment is characterized, and the measurement campaign are shortly described. The following models have been analyzed: the COST231 Walfisch-Ikegami model, the modified COST231Walfisch-Ikegami model tuned on the basis of empirical data, and the empirical...
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Modelling method for a class of distributed-lumped parameter systems
PublicationThe paper presents an alternative approach for modelling and order reduction of continuous system. The proposed methodology combines application of two methods: the modal decomposition method and the rigid finite element method. The given continuous structure is divided into 1D continuous substructures. For each 1D substructure modal decomposition and reduction procedure is applied. Interactions between substructures are described...
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Software tool for modelling of mechatronic systems with elastic continua
PublicationThe paper presents a systematic computational package for modelling and analysis of complex systems composed of multiple lumped and distributed parameter subsystems. The constructed computer program enables the frequency domain analysis of a class of linear systems and to obtain reduced order model in the form of bond graph. Obtained modal bond graph can be directly exported into 20-Sim package to further processing including nonlinear...
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Modelling of heat and mass transfer through wooden buildings
PublicationThe aim of this review paper is to examine the most recent available studies dealing with theoretical, numerical and experimental aspects related to modelling of heat and mass transfer through wooden buildings. The main thermophysical, mechanical and hygrometric properties of wood are firstly discussed. Then, the basic governing equations of heat and mass transfer phenomena are presented. A detailed description of the physical...
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Modelling of performance of an AUV stealth vehicle. Design for operation.
PublicationIn the paper some results of research connected with modelling of performance and risk assessment of an AUV stealth vehicle are presented. A general approach to design of the stealth AUV autonomous underwater vehicle under consideration is introduced. The basic stealth characteristics of the AUV stealth vehicle are briefly described. The method of research is introduced. The AUV stealth vehicle concept is presented including the...
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A two dimensional approach for modelling of pennate muscle behaviour
PublicationThe purpose of this study was to elaborate a two-dimensional approach for unipennate and bipennate striated skeletal muscle modelling. Behavior of chosen flat pennate muscle is modelled as a rheological system composed of serially linked passive and active fragments having different mechanical properties. Each fragment is composed of three elements: mass element, elastic element and viscous element. Each active fragment furthermore...
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GENERALISED HERSCHEL MODEL APPLIED TO BLOOD FLOW MODELLING
PublicationThis paper introduces a new rheological model of blood as a certain generalisation of the standard Herschel-Bulkley model. This model is a rheological constitutive equation and belongs to the group of the so-called generalised Newtonian fluids. Experimental data is compared with results, obtained from the new model, to demonstrate that it allows for the best agreement together with Luo-Kuang model. The new model may be easily implemented...
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Computational modelling of historic masonry railroad arch bridges
PublicationThe problems encountered during the analyzes of structural response of historic masonry railroad arch bridges are described in this paper. The attention is mainly focused on the stiffness of the masonry arches, their strengths and appropriate estimation of railroad load intensity. Issues related to computational modelling of two, existing, almost 130 years old masonry arch railroad bridges are presented in this context. The main...
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Modelling the loss of time caused by traffic incidents on motorways
PublicationFor each road incident important factors like location, capacity reduction, traffic management, duration of road incidents and amount of traffic should be defined. All performer operations and effects of incidents affect the capacity of the road, average speed, time loss, vehicle queues and traffic jams. In the article road incidents were divided into planned and unexpected. Statistical analysis prepared using the database of traffic...
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Modelling and analysis of medium frequency transformers for power converters
PublicationThe evolutions in power systems and electric vehicles, related to the economic opportunities and the environmental issues, bring the need of high power galvanically isolated DC-DC converter. The medium frequency transformer (MFT) is one of its key components, enabled by the increasing switching frequency of modern power semiconductors like silicon carbide transistors or diodes. The increased operating frequency offers small...
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GIS three-dimensional Modelling with geo-informatics techniques
PublicationThe integration issue of virtual models and geo-referenced database have a very broad spectrum of potential applications. Before the integration issue was on the cusp, it was quite problematic to combine three-dimensional models with the geo-referenced database. An integrated database contains a variety of data including such as object orientated data model and raster data. Within this paper, authors present an integration process...
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Modelling the set of earthworks machinery with the use of computer simulation
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Modelling of acoustic heating induced by different types of sound
PublicationWyprowadzono równanie dynamiczne sterujące ogrzewaniem na skutek strat energii fali akustycznej dowolnego typu, okresowej i nieokresowej, w płynie ze standardową dyssypacją i przewodnictwem ciepła. Zbadano efektywność ogrzewania w przypadku dźwięku stochastycznego i regularnego.
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Mathematical Modelling and Computer Simulation of Activated Sludge Systems
PublicationPrzegląd systemów osadu czynnego. Rozwój modeli procesu osadu czynnego. Podstawowe definicje z zakresu modelowania matematycznego i symulacji komputerowej. Proces budowy modelu (model biokinetyczny, hydrodynamiczny, transferu tlenu, temperatury). Modelowanie procesów biochemicznych zachodzących w systemach osadu czynnego. Organizacja badań symulacyjnych. Praktyczne zastosowania modeli osadu czynnego.
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Lipid-protein interactions in membranes: a molecular modelling study
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Propagation Path Loss Modelling in Container Terminal Environment
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Machine Learning Modelling and Feature Engineering in Seismology Experiment
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Nonlinear control systems modelling: global vs. local
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Using UML/WS-CDL for modelling negotiation scenarios
PublicationW celu usprawnienia realizacji przedsięwzięć ludzkich w Internecie potrzebne jest zdefiniowanie reguł i procedur komunikacji pomiędzy uczestnikami. Scenariusze przedsięwzięć mogą być wyrażane w językach opisu choreografii. Artykuł prezentuje metodologię tworzenia scenariuszy w języku WS-CDL oraz wyniki eksperymentów polegających na przeprowadzeniu negocjacji w Internecie z wykorzystaniem różnych scenariuszy negocjacyjnych.
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On finite element modelling of architectural fabrics for hanging roofs
PublicationArtykuł dotyczy modelowania konstytutywnego i identyfikacji parametrów materiałowych dla tkanin technicznych powszechnie stosowanych w konstrukcjach membranowo-cięgnowych. Autorzy przedstawiają krótką charakterystyke modeli stosowanych w opisie zachowania sie tkanin technicznych. Opisano metodę do idetyfikacji nieliniowo-sprężystych właściwości tkanin technicznych. Dodatkowo dokonao porówania wyników z prób jednoosiowego rozciągania...
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COMPREHENSIVE MODELLING OF THE COST EFFECTIVNESS OF RAILWAY LINE ELECTRIFICATION
PublicationSubject of this paper is the mathematical model estimating the Economical threshold between usage of combustion engine traction and electrical traction for new and modernized railway passenger communication lines. Currently available models do not coincide with the whole complexity of the problem. The proposed model was implemented into Matlab and then validated on “Pomorska Kolej Metropolitalna” investment time-frame and its cost...
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Numerical FDM modelling of wave propagation in concrete structure
PublicationThe article presents application of finite difference method to damage detection and its size evaluation in concrete structure by elastic wave propagation method. The simulations of wave propagation in concrete structure were performed for six different damage scenarios. Damages were modelled as areas with changed material properties. Investigation focused on the influence of damage size on the energy of wave reflection. Presented...
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Applying Generative Modelling Tools to Explore Architectural Forms
PublicationThe digital generative methods open up new areas for exploration of formal and tectonic features, accentuate form’s ability to emerge and perform. They allow for automatic generation of variations of solutions, and digital production of “difficult” components of architectural forms using CNC technology.The paper deals with contemporary architectural explorations of complex , curvilinear surfaces in the context of generative...
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Secondary arc modelling for single pole reclosing analyses
PublicationThe paper discusses two evaluation methods of single pole auto-reclosing process effectiveness in HV transmission lines. Secondary arc current and recovery voltage calculation results obtained by load flow calculation are compared to the results obtained by the time domain simulations. Moreover, a nonlinear secondary arc model implementation is presented. The paper presents the study results for the three types of EHV transmission...
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Strength parameters of masonry walls in modelling historic constructions
PublicationThe paper presents the determination of the basic material properties of a historic brickwork. Experimental studies were used to identify the basic material properties of bricks. The mechanical properties of the masonry, as an orthotropic homogenized material, were calculated. Then, numerical simulations using the Finite Element Method (FEM) were performed to verify the experimental outcomes. Macromodels with element sizes of 40,...